Strip and keep map

Direct plug-in build list

Plan change (user, 2026-10-18): no separate adapter. The modified 98 engine harness ends in the 88 N3/N5 plug halves (cut from the old 3VZ harness) and plugs straight into the truck's 88 body plugs. The 98 cowl plugs II1/II2/II3 drop out. Each kept 98 wire is de-pinned from its II cavity and pinned into its N3/N5 cavity. The truck's own 88 body plugs are never touched, so the whole thing still unplugs.

The old adapter version is in _archive/2026-10-18-pre-direct/adapter-build-list.md. (The filename stays the same because rebuild/tools/build_binder.py reads it.)

Do the checks before crimping: checks 1–4 in wiring-checks.md, the bench beeps in research/P-3vz-harness-salvage.md, and the reach + terminal tests below.

Ground rules (unchanged)

• Pins and de-pins only. No splices or butt connectors. Joins are plug-type: junctions B–E = Toyota-style joint connectors (bus-bar plug) or two wires in one terminal. Junction A = one heavy 12–14 AWG terminal (it carries starter-solenoid current).
• Wire IDs: 98 cavity numbers are from EWD319U. Your 98 plug cavities couldn't be read in the photos, so find each 98 wire by its color and confirm the cavity. 88 cavities were read on your truck: sockets, counted left to right, clip on top, looking into the front.
• N5 numbering note: the page drew N5's short bottom row so the large black-red wire reads as 14; theMonch calls it N5-15. It's the same cavity, the large black-red one. Go by the wire.

First: two tests that decide whether direct plug-in works

1. Reach test. Lay the 98 harness in the truck the way it will run (through the firewall, toward where the II joint used to be). Each 98 wire in table 1 must reach its N3/N5 cavity with 2–3" of slack, plus about 1" that you lose cutting the old terminal off. A wire that's short can't be lengthened (no splices): replace it end to end, or build that circuit as a new wire in table 2.
2. Terminal test. Push one 98 terminal into an empty N5 cavity. If it locks: re-use the 98 terminals. If it doesn't (likely): cut it off and crimp on a new 88-type terminal that matches the N3/N5 housing (IWS-1424A).

1. 98 harness wires: move from the II plug into N3/N5

2. E12 branch: new wires (the 98 body harness that fed E12 isn't in the truck)

E12 is your cut pigtail. Re-pin it with new wires. These are new wires in both plans, because nothing in the 88 body reaches E12.

3. Junctions (one wire in, several out)

4. 88 branches salvaged whole (switch plugs untouched)

5. Relays, kill switch, OBD (mounted as a short branch near N3/N5)

6. Charging and starter side (98 Engine No.2 / EA1)

• Alternator: CS144 140 A + CS144 adapter harness (decided 2026-10-13; harness BOUGHT 2026-10-18). The harness goes from the 5VZ/3.4 harness's alternator plug to the CS144, so the plug fit is solved. The IG / L / S feeds still come from the 88 side by function (check 9).
• Never put the 88 alternator plug on a 98-style alternator: the pin order differs (98: 1 L, 2 IG, 3 S; 88: 1 S, 2 L, 3 IG). Join by function, checked with a meter (check 9): IG = 88 RED (ENGINE 15A, key ON), L = 88 YEL (charge lamp), S = 88 WHT (constant 12 V).
• EA1-3 B-W → starter 50 is junction A's heavy leg. The 98 S1 plug fits the 5VZ starter.
• Battery moving to the driver side: B cable and grounds sized after mock-up (2 AWG or 1/0).

7. Leave empty in the N3/N5 halves

• N5: 7 (G-Y → old ECU T-3; not BATT), 16 (B → old ECU S-12 + OX, the 3VZ O2 line; not tach, cut-log 2026-10-21). 10, 13 and 15 are empty.
• N3: 4 (empty), 9 (W-G) and 10 (W-R), the old idle-up VSV. N3-10 is live with the key ON (IGN 7.5A): its body-side terminal stays inside the plug while connected, but never leave the body plug hanging loose with the key on. If the A/C clutch won't engage in check 12, a 39 Ω 5 W resistor across N3-10 / N3-9 stands in for the old VSV.
• Now used, no longer empty: N5-1 (Relay B trigger), N5-11 (4WD switch ground, new ~7 ft wire), N5-3 (BR; 2026-10-21: body side has a BR wire but it's open to chassis, so a body device took its ground through the engine harness. Pin an 18 AWG engine-ground wire into N5-3, to the 98 EC ground eyelet. Which body device: UNVERIFIED, no EWD040U).

8. De-pin and remove from the 98 harness

• Everything else that ran through II1/II2/II3 and is not in table 1 (A/T, cruise, ED1, II3-19/20 reverse pair, II3-24 shield, ACT E12-5): per harness-strip-list.md and print/98-connector-diagram.html (Strip & keep view).
• II3-2 (NSW) must never be grounded (P1780). It's removed with the A/T branch; tape its ECM end if it stays in E9.
• Once table 1 has been moved, the II1/II2/II3 housings are empty. Keep them (don't throw them out) in case you go back to the adapter plan.

Wire count

• 11 98 harness wires to move
• 6 new E12 wires
• 5 junctions
• 4 salvaged 88 wires
• 2 relays, 1 kill switch, 1 DLC3

Later

• Aux fuse block (constant + key-switched sections) for the accessories (light bar, stereo/amp, USB). When it goes in, move the OBD pin 16 feed onto its constant side and remove the add-a-fuse. The winch goes straight to the battery, not through the block.

Meter checks, in order

From the full-OEM audit (research/M-full-oem-audit.md, every value sourced there). Meter = multimeter. "Body side" = the truck's N3/N5 plugs with the old engine harness unplugged.

Plan (2026-10-18): direct plug-in. The 98 harness ends in the salvaged 88 N3/N5 halves; there is no separate adapter. Build list: adapter-build-list.md. Session notes: research/P-3vz-harness-salvage.md.

Do 0a–0c and 1–4 before you crimp anything. 5–9 when the harness is built. 10–18 at first start and the first drive.

Most important three:

• Check 4 finds which N5 wire feeds the A/C amplifier's engine-speed input (amp pin 5, black, behind the glove box). Without it the A/C clutch probably won't engage (RM077U AC-46 shows the amp expects 10–14 V on pin 5 with the engine running). If N5-6 beeps to pin 5, the split is body-side and nothing extra is needed.
• Check 13b confirms the AC1 relay raises the idle with the A/C on.
• Check 3 confirms N5-12 is the EFI relay's output (the easiest way: beep N5-12 to ECU plug S-13/S-14 on the old 3VZ harness).

Bench checks on parts (any time)

• A/C compressor fit: the 88 compressor is still on the truck with its lines attached (system sealed). Once the 5VZ is in, bolt the 88 compressor (with the 5VZ pulley + clutch plate, shim kept) to the 5VZ bracket. Straightedge across the crank and compressor pulleys: in line. Check the low-side line clears the upper control arm.
• A/C refrigerant: read the under-hood sticker / fittings: R-12 or converted R-134a? The system was left sealed, so it may still be charged: if the clutch engages in check 12 and it blows cold, no shop visit is needed.
• Alternator plug: test-fit the 88 alternator plug into the 98 alternator socket (point 3, parked).
• Sender threads: hand-thread the 88 oil sender and the 88 temp sender 2–3 turns into the 5VZ ports (or the removed 98 parts' holes). Assumed 1/8 PT (28 TPI); not confirmed. Oil sender: 15 N·m, Loctite 242/243 on 2–3 threads, no PTFE tape (it grounds through the threads).
• Oil sender clearance: trial-fit with the oil filter on; check the filter wrench and the 88 dipstick tube clear.
• 4WD switch: DONE 2026-10-18: 2 wires. LG (teal) → junction D (reaches). W-B ground is too short → new ~7 ft wire to N5-11.
• Towing package: look for an "A/C cut" relay near the A/C amp. If it's there, tell Claude; there's an A/C temp switch to trace.
• 98 alternator tag: 60 A expected. If it's bigger, upgrade the B wire and AM1 link.
• EFI fuse in the 88 relay box: confirm it's 15 A.
• Injectors: bluetops ~12–14 Ω (the 88 V6 used low-impedance injectors with a resistor; those must not go on the 98 ECM).

3VZ harness cut log

Read this right before cutting. It lists the bench checks that need the old 3VZ harness still whole, their results, and what to keep or cut on each wire.

Background: research/P-3vz-harness-salvage.md. Plan: adapter-build-list.md. Checks: wiring-checks.md.

Rule: don't cut a wire until its check below is done. Photograph and label every kept wire with its N3/N5 cavity before cutting.

Done

To do before cutting the rest

2026-10-21: N5-7 and N5-16 de-pinned from the old N5 half; terminals bagged as spares. Old N5 half now holds 11 wires (1, 2, 3, 4, 5, 6, 8, 9, 11, 12, large B-R), colors confirmed (user). Straight-in cavities (2, 4, 5, 6, 8, B-R) keep their old wire until the 98 wire replaces it. N3: all 9 wires confirmed (1, 2, 3, 5, 6, 7, 8, 9, 10); N3-9 and N3-10 de-pinned (2026-10-21), terminals bagged. N3 now holds 7. Harness CUT 2026-10-21 (user): 12" tails on N3/N5; 4WD (N3-1), reverse (N3-2/6) and starter (N5-9) branches kept whole; 6" sender + clutch pigtails; the rest scrapped.

Keep list (don't cut these)

• N3 and N5 halves with ~12" of every kept wire. De-pin, don't cut, the unused cavities (spare terminals).
• Reverse switch branch, whole (R / R-B → N3-2 / N3-6).
• 4WD switch branch: LG through the splice to N3-1; stubs as above.
• Starter signal wire N5-9 → starter plug (if reusing).
• Temp sender plug (Y-G), oil sender plug (L-B): ~6" pigtails each (backups if the 98 plugs won't fit the 88 senders). A/C clutch (B-W) pigtail NOT needed (2026-10-21: adapter = 98 A2 mating plug → ring terminal on the 88 clutch).
• Whatever check 1 finds for the alternator wires.
• Old ECU plugs: keep until every check above is done.

98 engine harness: every plug

3VZ harness salvage notes

What to keep from the old 3VZ-E engine harness, what the user found while stripping it, and the related tool and cleaning advice.

Sources: adapter-build-list.md, rebuild/swap-steps.md T1, research M, EWD319U Component Locations p.27, plus what the user saw on the harness (marked User).

Keep from the 3VZ harness

Not needed: the ECU plugs (keep them until check 3 is done), cold-start injector, EGR/VSVs, check connector, idle-up VSV, alternator plug (CS144 + TEQ harness), and the 3VZ ground branch apart from the 4WD leg below.

Bench checks with the old harness still whole

• [x] N5-12 mating cavity ↔ ECU S-13/S-14 beep → N5-12 = EFI relay output (check 3, block B). Result (User, 2026-10-19): beeps to both (spliced), and the wire continues farther up the harness (other 3VZ +B loads). Check 3a PASSED.
• [ ] Starter plug terminal ↔ engine-side N5-9 beep → confirms the start-signal wire.
• [ ] N5-3 (BR) engine side ↔ ground eyelet. Then on the truck: N5-3 body side → chassis Ω (check 4).
• [ ] N5-11 body side → chassis ≈ 0 Ω (truck, old harness unplugged). Open → ground the 4WD W-B to the frame with a ring terminal instead.

What the user found on the harness (User, 2026-10-18)

• Starter: the small black wire is NOT a ground. It's the terminal 50 start signal from N5-9 (B, the 88 starter relay output). On the 3VZ it splits to the solenoid, old ECU STA, the cold-start injector and the start-injector time switch (research M §7). In the swap block A replaces all of it: N5-9 → block A → 98 EA1-3 → 5VZ starter 50, with the STA tap to II1-6. The starter grounds through its case. The heavy straps (battery − ↔ block ↔ body) matter, not a harness wire (check 1).
• Reverse switch branch: R + R-B, both to N3. Matches N3-2 / N3-6, polarity doesn't matter. ✓
• 4WD switch branch: 2 wires.
• LG → factory splice → N3-1 (4WD light) and old ECU S-16 (4WD input). The S leg's job moves to II3-9.
• W-B (ground, Mitchell 5-607) → factory splice with BR → N5-11. The same brown ground splice also fed old ECU U-7 and the shield drain of a shielded cable (W, R, G, B wires) from ECU plug T. U-7's function isn't in our files (UNVERIFIED; probably an ECU ground). The plug-T cable is 3VZ-only.
• Plan: pin W-B into N5-11 in the adapter. Trim the U-7 and shield legs back and seal them. Written into adapter-build-list.md, and N5-11 was taken off the "unused" list.
• Corrected (2026-10-18): the LG (teal) reaches junction D. It's the W-B ground that's too short. Replace the W-B (de-pin it at the switch plug) with a new ~7 ft wire routed with the harness to N5-11: the stock ground path, decided by the user. Frame ground is the fallback only if N5-11 isn't grounded.

Using the 98 1-wire plugs

• A/C clutch (98 A2, II3-25 LG-B, 1-pin): N3-3 → block C → II3-25 → plug. Grounds through the compressor body. Test-fit on the 88 compressor. If it doesn't fit, use a plug-to-plug pigtail (don't re-terminate), so the later 98 compressor plugs straight in.
• Temp gauge (98 W2, II3-21 Y-R, 1-pin): N3-7 → II3-21 → 88 sender (the 98 sender reads 234–314 Ω at 50 °C vs about 147 Ω at 60 °C for the 88, so the gauge would read low). If the plug doesn't fit, re-terminate: de-pin the 98 terminal, crimp on the 88 terminal, use the 88 housing. Hand-thread the 88 sender into the 5VZ port first (1/8 PT assumed, UNVERIFIED).
• Where W2 is (EWD319U Component Locations p.27 [5VZ-FE]): front center of the engine, at the front of the V between the heads, on a short branch off the engine harness trunk that runs across the front. Identify it by the 1-pin Y-R plug. Don't confuse it with the 2-pin ECT plug EC1 or the 1-pin G-W oil switch O1.

Crimp tool (2026-10-18)

• Buy the IWISS IWS-1424A (open barrel, 24–14 AWG, $17.99). The 1424B and 1420D are Weather Pack / Metri-Pack crimpers; Toyota uses open-barrel F-crimp terminals.
• Limits: tops out at 14 AWG, so build block A in 14 AWG (or crimp 12 AWG with another tool). Two 18 AWG wires in one terminal ≈ 15 AWG: test-crimp first.
• Better fit for small Japanese terminals: Engineer PA-21. Either way, test-crimp scraps first.
• Still need terminals that match each Toyota housing (separate purchase).

Cleaning the harness

• Don't soak it in a bucket of degreaser. It wicks into connectors and strands, can swell seals and old PVC, and leaves residue that corrodes the terminals.
• Do this instead: strip first, peel the old tape, wipe with a rag of diluted Simple Green or IPA, bag the plugs, use electrical contact cleaner inside the connectors, blow it dry, and let it sit a day.

OBD-II port (DLC3), decided 2026-10-18

• User's 98 pigtail has ~12" leads: GR-W (larger: shield jacket around the W data wire + a drain) = pin 7 · W-B = pin 4 chassis ground · BR-R = pin 5 signal ground (II3-18) · V = pin 16 constant 12 V.
• Mount by the glove box, next to the 98 ECM, which goes where the 88 ECU was. The leads reach, the shielded data cable stays intact, and no DLC3 terminals are needed. Ground the shield drain at the ECM/EC end only.
• Pin 16 power: add-a-fuse (7.5A) in a constant slot of the 88 fuse box for now. Later move it to an aux fuse block (constant side) that's added with the accessories. Don't share the ECM BATT feed.
• Check whether the 12" V lead reaches the 88 fuse box. If not, pin a longer wire into pin 16.

Terminal test and order counts (2026-10-18)

• 98 and 88 terminals are NOT the same (user de-pinned one of each). Every 98 wire that goes into N3/N5 gets a new 88-type terminal crimped on.
• 88-type for N3/N5: 13 small (N5-1, 2, 4, 5, 6, 8, 11, 12 · N3-1, 3, 5, 7, 8), +1 for N5-3 (engine-ground wire, 2026-10-21; junction E dropped), and 2 large (N5 large B-R, N5-9). N3-2/N3-6 keep their original reverse-switch terminals. UNVERIFIED: whether N5-12 is a small or a large cavity. Order 25 small + 5 large.
• 98 E12: 6 (8, 12, 14, 16, 23, 24). Order 10.
• 2026-10-19 (user): ECU pins are male, 1.0 mm wide; the E12 housing is stamped AMP 11218, probably Toyota housing 90980-11218 (inferred). Best online lead: Ballenger Motorsports CONN-100819, a Tyco/AMP 1.0 mm female Toyota ECU terminal, 20–16 AWG, $0.69 each. It's listed for housings 90980-11214/11215 (the AMP 11214/11215 stamps on Supra ECU plugs), so 11218 is UNVERIFIED: email them to confirm first. Avoid generic Amazon kits.
• DLC3: none (the 12" pigtail leads are reused).
• Other: ~15 joint-connector terminals (junctions A–E, A heavy), 8 relay-socket terminals, 1 for the 4WD switch plug (new W-B), 2 ring terminals.
• Part numbers: not in our manuals. Measure the de-pinned terminals' blade or socket width and match by that.

Plan change: direct plug-in (2026-10-18)

The modified 98 harness pins straight into the salvaged 88 N3/N5 halves. II1/II2/II3 drop out, and there is no separate adapter. Junctions, relays, kill switch, E12 wires and the DLC3 are still needed: they exist because the 98 engine and the 88 body don't match one to one, not because of the adapter. Build list: adapter-build-list.md (rewritten). The old adapter version is in _archive/2026-10-18-pre-direct/.

Why the AC1 idle-up relay is needed (2026-10-18)

• The problem: the compressor loads the engine at idle, so the ECM has to open the IAC before the load arrives. On a 98, the 98 A/C amp grounds the ECM's AC1 input (E12-16) to ask for idle-up. On the 88, the 88 amp powered an idle-up VSV on the 3VZ (N3-9/N3-10). That VSV doesn't exist on the 5VZ, and the 88 amp has no wire that talks to a 98 ECM.
• Without it (research N, YotaTech thread 251179, ORS): idle sags to ~500 rpm when the clutch engages → the 88 amp's low-rpm cut-out drops the clutch → idle recovers → clutch re-engages → idle hunting and weak A/C at stops.
• Why a relay: the polarity is opposite. The 88 amp's clutch output (N3-3) goes to +12 V when the A/C is on, while AC1 wants to be pulled to ground (RM580U terminal values: 9–14 V A/C off, < 2.0 V A/C on). A wire or diode can't invert that; a relay can. Coil: junction C → ground. Contact: E12-16 → ground. It also isolates the 88 amp from the ECM input (forum: AC1 tied straight to the old amp → idle stuck near 1,200 rpm).
• History: 2026-10-07 plan read AC1 as an A/C cut and left it open, with an ACT (E12-5) diode instead. 2026-10-12 (research N + RM580U) showed AC1 is the idle-up input → relay added. ACT then skipped (user's call; it only reports clutch engaged).
• Verify (check 13b): warm idle, E12-16 reads 9–14 V A/C off, < 2.0 V A/C on, idle holds about 700 or rises slightly. If the clutch still drops out at idle, adjust the 88 amp's cut-out pot.
• Sources: the AC1 voltages are from the factory manual (RM580U). The symptom and the relay fix are from forums, not an FSM.

How sure is this plan? (2026-10-18)

Mistake made and fixed on 2026-10-18: the small black wire at the 3VZ starter was first called a ground. It's the terminal 50 start signal from N5-9.

Updates (user, 2026-10-18): no emissions testing in the user's county, so it's not a concern. The CS144 adapter harness (5VZ/3.4 harness → new alternator) is bought.

Fuel: DW200 and the stock ECM with bluetops (2026-10-18)

• Pump: user is switching to the DW200 (255 L/h). DW's sheet gives ~9.2 A at 40 psi and ~10.4 A at 60 psi (DW100: 4.2 A). Relay B is now 12 AWG feed and ground, 20A fuse, 30 A relay. All docs updated. The stock ECM doesn't care which pump is fitted; the regulator sets the pressure.
• Stock 98 A/T ECM + 315cc bluetops: not recommended. The ECM's fuel maps assume the stock 5VZ injectors (~240 cc, user's 23250-62030). At the same pulse width the bluetops flow about 30% more (312–315 / 240 ≈ 1.3).
• Idle and cruise (closed loop): the O2 sensors trim fuel back, but 30% is at or past the usual trim range [assumed: Toyota trims run out around ±20–25%; not in our FSMs]. Expect rich codes (P0172), a rough idle, fouled plugs.
• Cold start, WOT and boost (open loop, no O2 correction): about 30% rich. That's the worst place for it with the MP62, and it's hard on the new cat.
• The Magnuson MP62 kit is calibrated for stock injectors, stock pressure and the stock ECU (manual p.1–3, research O).
• Recommendation: to drive on the stock ECM, run the stock 5VZ injectors (you have them) with the MP62, exactly as Magnuson intended. Put the bluetops in when the aftermarket ECU goes in and tune for them. Not recommended: dropping the fuel pressure to compensate (you'd need ~25 psi; poor atomization).
• Stock ECM as a limp-home backup with the bluetops (2026-10-18): probably yes, for a gentle drive. It plugs into the same E9–E12 plugs as the planned plug-in aftermarket ECU, so swapping back is plug-and-play. Drive at light throttle and low rpm to stay out of boost, keep it short, expect the MIL and a rich, rough idle, and watch for misfires (they overheat the cat). Not tested on this engine; it's reasoning, not a verified result. Keep the stock ECM and a spare set of plugs in the truck.

98 starter/alt harness: the heavy black cable (2026-10-19)

• The 98 starter/alt harness (Engine No.2 wire + battery cables) has a heavy black cable that isn't joined to the + cables. It's the engine ground strap: battery area → engine block under the oil filter (User, from a donor photo).
• FSM: RM580U EM-72 step 10(a) / EM-76 step 5(c) "ground strap" (drawing S02115 shows only the battery-side bolt). EWD319U doesn't draw it. The engine-end location comes from the user's photo only.
• Swap: reuse it as the block → battery − cable if it reaches the relocated driver-side battery. Clean the block boss to bare metal. Check 1 still applies.

3VZ starter signal wire traced (User, 2026-10-19)

• The 88 starter signal wire (black) on the 3VZ harness connects N5-9, the starter 50 plug, old ECU U-1 (NSW) and U-3 (STA), and more splices farther up the harness (cold-start injector / start-injector time switch per research M §6). Matches M5-604.
• User is considering reusing it as the starter-50 wire instead of 98 EA1-3 (runs with the trans branches, easier route). Undecided. If used: keep only N5-9 → starter; trim and seal U-1, U-3, cold-start and time-switch legs; feed the 98 ECM STA (E9-13) by crimping the 98 B-W into the same N5-9 terminal (junction A as two wires in one terminal).

88 plugs, face-on

1988 4Runner 3VZ-E → 98 5VZ-FE · read on the truck 2026-10-12

Connector Diagram

What you read on each plug, laid out face-on so you can check it against the real thing one last time. Colors are your readings; jobs come from the 1988 Mitchell V6 page (ECU plugs) and theMonch's chart (body plugs). The ECU plugs are on the old 3VZ harness and go away; they're here because they prove which body-plug wire is which.

carries a swap wireold 3VZ wire, not usedempty cavitynot recorded: check itlarge cavity

N5 numbering: the large black-red ignition wire shows here as 14; theMonch calls it N5-15. Same cavity. Build by the wire.

ECU plug S

24 cavities · on the old 3VZ engine harness · photo IMG_3852 · 8 swap wires

CLIP · TOP

1empty

2Green-Yellow

3Blue-White

4Yellow-Red

5Blue

6Green-White

7Green-Red

8empty

9empty

10empty

11empty

12Black

13Black-Yellow

14Black-Yellow

15Blue-Green

16Light green

17Black

18Blue-Red

19Yellow

20Black-White

21empty

22empty

23Brown

24Brown-Black

Looking into the front (the end that plugs in), clip on top. Sockets: numbered left to right.

Pin	Wire	What it is
1	empty
2	Green-Yellow (G-Y)	BATT, constant 12 V → body N5-4
3	Blue-White (L-W)	VC (old airflow meter)
4	Yellow-Red (Y-R)	VS (old airflow meter)
5	Blue (L)	THA (old airflow meter)
6	Green-White (G-W)	STP brake → body N5-5
7	Green-Red (G-R)	SPD speed → body N3-5
8	empty
9	empty	A/T only (L2)
10	empty	A/T only (L1)
11	empty
12	Black (B)	OX (old O2 sensor)
13	Black-Yellow (B-Y)	+B1 main power → body N5-12
14	Black-Yellow (B-Y)	+B main power → body N5-12
15	Blue-Green (L-G)	TSW
16	Light green (LG)	4WD → body N3-1
17	Black (B)	KNK (old knock sensor)
18	Blue-Red (L-R)	AS (air-suction valve)
19	Yellow (Y)	W check engine → body N5-2
20	Black-White (B-W)	A/C → body N3-3
21	empty	A/T only (ECT)
22	empty	A/T only (L3)
23	Brown (BR)	E11 ground
24	Brown-Black (BR-B)	E21 ground

ECU plug T

18 cavities · on the old 3VZ engine harness · photo IMG_3851 · 0 swap wires

CLIP · TOP

1Green-Blue

2Black-White

3Green-Yellow

4White

5Green

6Red

7Black

8Black-Red

9empty

10Brown-Black

11empty

12Yellow

13White-Blue

14White-Red

15Green

16Red-White

17White-Green

18Blue

Looking into the front (the end that plugs in), clip on top. Sockets: numbered left to right.

Pin	Wire	What it is
1	Green-Blue (G-L)	THW coolant temp
2	Black-White (B-W)	IGF
3	Green-Yellow (G-Y)	HT O2 heater
4	White (W)	NE crank signal
5	Green (G)	G2 cam signal
6	Red (R)	G1 cam signal
7	Black (B)	G−
8	Black-Red (B-R)	FPU
9	empty
10	Brown-Black (BR-B)	E2 sensor ground
11	empty
12	Yellow (Y)	EGR
13	White-Blue (W-L)	IDL
14	White-Red (W-R)	VTA throttle
15	Green (G)	T (check connector)
16	Red-White (R-W)	VF (check connector)
17	White-Green (W-G)	ACV old idle-up valve
18	Blue (L)	THG

ECU plug U

10 cavities · on the old 3VZ engine harness · photo IMG_3850 · 1 swap wire

CLIP · TOP

1Black

2Green-Red

3Black

4Black-White

5Brown

6empty

7Brown

8Red

9Black-Red

10Brown

Looking into the front (the end that plugs in), clip on top. Sockets: numbered left to right.

Pin	Wire	What it is
1	Black (B)	NSW (B or B-W) · starter relay on M/T
2	Green-Red (G-R)	STJ old cold-start injector
3	Black (B)	STA starter signal → body N5-9
4	Black-White (B-W)	#10 injectors
5	Brown (BR)	E01 ground
6	empty
7	Brown (BR)	E1 ground
8	Red (R)	IGT igniter
9	Black-Red (B-R)	#20 injectors
10	Brown (BR)	ground

Body plug N5

16 cavities · truck side · photo IMG_3854 · large cavities: 9, 10, 14, 15 · 8 swap wires

CLIP · TOP

1Blue

2Yellow

3Brown

clip

4Green-Yellow

5Green-White

6Blue-White

7Green-Yellow

8Green

9Black

10empty

11Brown

12Black-Yellow

13empty

14Black-Red

15empty

16Black

Looking into the front (the end that plugs in), clip on top. Sockets: numbered left to right.

Pin	Wire	What it is
1	Blue (L)	not used in the swap
2	Yellow (Y)	Check engine ← 98 II1-2 (V)
3	Brown (BR)	not used
4	Green-Yellow (G-Y)	ECU BATT ← 98 E12-14 (L-R) · continuity ✓
5	Green-White (G-W)	Brake STP ← 98 E12-24 (G-W)
6	Blue-White (L-W)	Tach ← 98 II3-15 (B)
7	Green-Yellow (G-Y)	not used (not BATT: continuity went to 4)
8	Green (G)	Fuel pump control ← 98 II3-26 (G-Y)
9	Black (B)	Starter STA (large) ← 98 II1-6 (B-W) + new wire to starter 50
10	empty
11	Brown (BR)	not used
12	Black-Yellow (B-Y)	+B main power ← 98 E12-23 + II3-16 (W-L) · relay-pull test first
13	empty
14	Black-Red (B-R)	IG2 ignition power (large) ← 98 II3-8 (B-R) · theMonch calls this 15
15	empty
16	Black (B)	not used

Body plug N3

10 cavities · truck side · photo IMG_3853 · 7 swap wires

CLIP · TOP

1Light green

2Red

clip

3Black-White

4empty

5Green-Red

6Red-Black

7Yellow-Green

8Blue-Black

9White-Green

10White-Red

Looking into the front (the end that plugs in), clip on top. Sockets: numbered left to right.

Pin	Wire	What it is
1	Light green (LG)	4WD light ← 98 II3-9 (G-B)
2	Red (R)	Reverse lights ← new R150 switch wire
3	Black-White (B-W)	A/C clutch ← 98 II3-25 (LG-B); diode to E12-5 ACT
4	empty
5	Green-Red (G-R)	Speed ← 98 E12-12 (G-O)
6	Red-Black (R-B)	Reverse lights ← new R150 switch wire
7	Yellow-Green (Y-G)	Temp gauge ← 98 II3-21 (Y-R)
8	Blue-Black (L-B)	Oil gauge ← 98 II3-22 (G-W) · 88 sender
9	White-Green (W-G)	old idle-up valve, not used
10	White-Red (W-R)	old idle-up valve, not used

Build list (direct plug-in, 2026-10-18: the 98 wires pin straight into the N3/N5 halves cut from the old 3VZ harness): swap-wiring/adapter-build-list.md. N5-11 = 4WD switch ground; N5-1 = Relay B trigger. Before crimping: the N5-12 relay-pull test, and N5-4 reads 12 V with the key off.

98 plugs, face-on

1998 4Runner 5VZ-FE harness · from EWD319U + RM580U DI-158 · read-only

98 Connector Diagram

Wire colors (reference)Strip & keep E9E10E11E12II1II2II3

Every cavity of the seven 98 plugs: number, Toyota terminal name, wire color. Tap "Strip & keep" to color each cavity by what to do with it. Open "Every cavity" under a plug for the full table with sources.

All seven plugs: 40 Keep 18 To 88 plugs 48 Remove 37 Empty

• Keep Leave it in place. Runs the engine.
• To 88 plugs Kept: re-pinned with a new 88-type terminal straight into the 88 N3/N5 halves, or into a junction, relay or DLC3 (direct plug-in, 2026-10-18). E12 cavities get new wires.
• Remove De-pin it from the plug and pull the wire out of the harness (cut it back at its branch). Nothing on an 88 with a manual and a 98 manual ECU uses it.

The rule: keep only what an 88 4Runner with its original manual transmission plus the 98 5VZ with a 98 manual-transmission ECM would use. Every other wire: de-pin it and remove it.

Whole branches to remove (cut only on the branch side of a shared splice):

• A/T solenoid plug (S1, S2, SL)
• ATF temp sensor. ⚠ Its BR-B ground is shared with the TPS, MAF, coolant and vapor sensors: cut only at the sensor side of the splice.
• No.2 speed sensor on the transmission (SP2)
• Park/neutral switch. ⚠ Keep the starter signal ECM E9-13 ↔ II1-6 intact.
• Transfer switches D3, D4, D5 and the whole ED1 ADD switch branch
• Everything in II2 (98 2-4 select)

The 88 transmission switches keep their own wiring: the R150 reverse switch and the transfer 4WD switch branches come out of the old 3VZ harness whole, switch plugs untouched, and are re-pinned only at the N3/N5 end (reverse → N3-2/N3-6 as-is; 4WD LG → junction D → N3-1 and ECM 4WD via II3-9; 4WD W-B ground → new ~7 ft wire → N5-11).

Removing a wire from NSW (E9-14 / II3-2) leaves it open, which is exactly what the A/T ECM needs. Just never ground it.

Before you cut: check each plug against the wire colors here. A few colors differ between Toyota's wiring diagrams and repair manual (noted in the tables); trust what's on the harness.

E9

ECM connector A (E9), 34-pin

17 Keep 7 Remove 10 Empty

CLIP · TOP

14WDGreen-BlackKeep

2L4Blue-RedRemove

3

4

5#60YellowKeep

6#50BlueKeep

7#40Red-BlackKeep

8#30GreenKeep

9#20WhiteKeep

10#10RedKeep

11S1Light green-RedRemove

12IGFBlack-YellowKeep

key

13STABlack-WhiteKeep

14NSWBlackRemove

key

15IGT3Black-WhiteKeep

16IGT2Brown-YellowKeep

17S2Light greenRemove

18

19

20

21

22RSCBlack-RedKeep

23RSOBrown-RedKeep

24IGT1Black-BlueKeep

25

26

27SLGreen-RedRemove

28E03BrownKeep

29

30OILViolet-YellowRemove

notch

31PSWPinkRemove

32

33E02BrownKeep

34E01BrownKeep

Drawn as you hold the harness plug, looking into its open end, clip on top (the mirror of Toyota's DI-158 drawing of the ECM).

Every cavity (34)

Pin	Name	Wire	What it does	Group	Do	Source
1	4WD	Green-Black (G-B)	4WD-engaged input from the ADD indicator switch (via ED1-2 and II3-9), also lights the meter 4WD lamp Keep per harness-strip-list: the 88 4WD switch feeds it through ED1-2.	body/dash	Keep	EWD p.75, 158, 164
2	L4	Blue-Red (L-R)	Transfer L4 position detect switch D4 (A/T shift logic)	98 4WD/ADD	Remove	EWD p.121, 169; RM DI-284 has no L4 entry (its TFN E11-9 line gives L-R and L4 logic)
3			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
4			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
5	#60	Yellow (Y)	Injector No.6 drive	engine	Keep	EWD p.75; RM DI-158
6	#50	Blue (L)	Injector No.5 drive	engine	Keep	EWD p.75; RM DI-158
7	#40	Red-Black (R-B)	Injector No.4 drive	engine	Keep	EWD p.75; RM DI-158
8	#30	Green (G)	Injector No.3 drive	engine	Keep	EWD p.75; RM DI-158
9	#20	White (W)	Injector No.2 drive	engine	Keep	EWD p.75; RM DI-158
10	#10	Red (R)	Injector No.1 drive	engine	Keep	EWD p.75; RM DI-158
11	S1	Light green-Red (LG-R)	A/T shift solenoid No.1	A/T only	Remove	EWD p.120; RM DI-284
12	IGF	Black-Yellow (B-Y)	Ignition confirmation signal from igniter I2-4	engine	Keep	EWD p.63, 77; RM DI-159
13	STA	Black-White (B-W)	Starter signal (cranking) via II1-6	engine	Keep	EWD p.63, 75; RM DI-158
14	NSW	Black (B)	Park/neutral start signal (A/T), fed from 7.5A STA via II3-2 and P1 Removing it leaves NSW open, which is what the A/T ECM needs. Never ground it.	A/T only	Remove	EWD p.63, 75, 120; RM DI-159, DI-284
15	IGT3	Black-White (B-W)	Ignition trigger 3 to igniter I2-5	engine	Keep	EWD p.63, 77; RM DI-159
16	IGT2	Brown-Yellow (BR-Y)	Ignition trigger 2 to igniter I2-6	engine	Keep	EWD p.63, 77; RM DI-158
17	S2	Light green (LG)	A/T shift solenoid No.2 (also spliced to II1-4 -> cruise ECU ECT)	A/T only	Remove	EWD p.120, 138; RM DI-284
18			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
19			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
20			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
21			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
22	RSC	Black-Red (B-R)	Idle air control valve close coil (I1-3)	engine	Keep	EWD p.76; RM DI-159
23	RSO	Brown-Red (BR-R)	Idle air control valve open coil (I1-1)	engine	Keep	EWD p.76; RM DI-159
24	IGT1	Black-Blue (B-L)	Ignition trigger 1 to igniter I2-7	engine	Keep	EWD p.63, 77; RM DI-158
25			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
26			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
27	SL	Green-Red (G-R)	A/T lock-up solenoid	A/T only	Remove	EWD p.120; RM DI-284
28	E03	Brown (BR)	ECM power ground (heater circuit) to EC	engine	Keep	EWD p.77, 121; RM DI-159 (HT1/HT2 reference)
29			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
30	OIL	Violet-Yellow (V-Y)	ATF temperature sensor A3	A/T only	Remove	EWD p.120; RM DI-284
31	PSW	Pink (P)	Power steering oil pressure switch P22 (idle-up). Removed 2026-10-19: 3VZ PS lines have no switch port	engine	Remove	EWD p.76; RM DI-159 (symbol PSSW)
32			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
33	E02	Brown (BR)	ECM power ground to EC	engine	Keep	EWD p.77, 121
34	E01	Brown (BR)	ECM power ground (injectors) to EC	engine	Keep	EWD p.77, 121; RM DI-158

E10

ECM connector B (E10), 22-pin

14 Keep 3 Remove 5 Empty

CLIP · TOP

1VCGreen-BlackKeep

2

3

4SP2-White-RedRemove

5NE+VioletKeep

6NE-PinkKeep

7VTABlack-YellowKeep

8VGRed-WhiteKeep

key

9SP2+Yellow-RedRemove

10

11

12PWRGreen-RedRemove

13OX1WhiteKeep

14KNK2GrayKeep

15KNK1BlackKeep

16

17G+BlueKeep

18FCGreen-YellowKeep

19OX2RedKeep

notch

20THWGreenKeep

21THAYellow-GreenKeep

22E2Brown-BlackKeep

Drawn as you hold the harness plug, looking into its open end, clip on top (the mirror of Toyota's DI-158 drawing of the ECM).

Every cavity (22)

Pin	Name	Wire	What it does	Group	Do	Source
1	VC	Green-Black (G-B)	5 V sensor supply (TPS, vapor pressure sensor)	engine	Keep	EWD p.75; RM DI-158
2			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
3			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
4	SP2-	White-Red (W-R)	A/T No.2 vehicle speed sensor V3 (-)	A/T only	Remove	EWD p.120; RM DI-284
5	NE+	Violet (V)	Crankshaft position sensor C2-1 (+)	engine	Keep	EWD p.63, 76; RM DI-159 says R
6	NE-	Pink (P)	Crank/cam sensor common (-), C2-2 and C1-2	engine	Keep	EWD p.63, 76; RM DI-159 says G
7	VTA	Black-Yellow (B-Y)	Throttle position sensor signal	engine	Keep	EWD p.75; RM DI-158
8	VG	Red-White (R-W)	Mass air flow meter signal	engine	Keep	EWD p.75; RM DI-158
9	SP2+	Yellow-Red (Y-R)	A/T No.2 vehicle speed sensor V3 (+)	A/T only	Remove	EWD p.120; RM DI-284
10			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
11			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
12	PWR	Green-Red (G-R)	A/T pattern select switch (PWR) via II3-6	A/T only	Remove	EWD p.121; RM DI-284
13	OX1	White (W)	Heated O2 sensor bank 1 sensor 1 signal (shielded)	engine	Keep	EWD p.76; RM DI-159
14	KNK2	Gray (GR)	Knock sensor No.2 via EB1-2 (shielded)	engine	Keep	EWD p.76; RM DI-159
15	KNK1	Black (B)	Knock sensor No.1 via EB1-1 (shielded)	engine	Keep	EWD p.76; RM DI-159
16			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
17	G+	Blue (L)	Camshaft position sensor C1-1	engine	Keep	EWD p.63, 76; RM DI-159 says Y
18	FC	Green-Yellow (G-Y)	Fuel pump control: grounds circuit opening relay coil via II3-26	engine	Keep	EWD p.74-75; RM DI-159
19	OX2	Red (R)	Heated O2 sensor bank 1 sensor 2 signal (shielded)	engine	Keep	EWD p.76; RM DI-159
20	THW	Green (G)	Engine coolant temp sensor via EC1-2 (G-Y on sensor side of EC1)	engine	Keep	EWD p.75, 120; RM DI-158 says G-R
21	THA	Yellow-Green (Y-G)	Intake air temp (in MAF)	engine	Keep	EWD p.75; RM DI-158
22	E2	Brown-Black (BR-B)	Sensor ground (TPS, MAF, ECT, vapor sensor, ATF temp); not chassis ground	engine	Keep	EWD p.75, 120; RM DI-158

E11

ECM connector C (E11), 16-pin

9 Keep 2 Remove 5 Empty

CLIP · TOP

1

2EVPWhite-GreenKeep

3WVioletKeep

4

5TE1Violet-WhiteKeep

6OIL-WYellowRemove

key

7E3Black-WhiteKeep

8TPCPink-BlackKeep

9TFNRed-GreenRemove

10HT2Red-WhiteKeep

11HT1Pink-BlueKeep

12

13PTNKYellow-BlackKeep

14

15

16E1BrownKeep

Drawn as you hold the harness plug, looking into its open end, clip on top (the mirror of Toyota's DI-158 drawing of the ECM).

Every cavity (16)

Pin	Name	Wire	What it does	Group	Do	Source
1			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
2	EVP	White-Green (W-G)	EVAP VSV V7	engine	Keep	EWD p.76; RM DI-159
3	W	Violet (V)	Check engine (MIL) lamp drive via II1-2 to meter C11	body/dash	Keep	EWD p.76; RM DI-159
4			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
5	TE1	Violet-White (V-W)	Diagnostic TE1 to DLC1-8. DLC1 removed 2026-10-19: keep this wire, cap its end where DLC1 was; jump it to engine ground (E1) for the timing check	engine	Keep	EWD p.76; RM DI-159
6	OIL-W	Yellow (Y)	A/T oil temp warning lamp drive via II3-12	A/T only	Remove	EWD p.121
7	E3	Black-White (B-W)	MAF sensor ground (M1-5)	engine	Keep	EWD p.75; RM DI-158 says 'E3 (E11-17)'
8	TPC	Pink-Black (P-B)	Vapor pressure sensor VSV V8	engine	Keep	EWD p.76; RM DI-159
9	TFN	Red-Green (R-G)	Transfer neutral position switch D5 (A/T)	98 4WD/ADD	Remove	EWD p.121, 158, 164; RM DI-284 says L-R
10	HT2	Red-White (R-W)	O2 sensor B1S2 heater drive	engine	Keep	EWD p.76; RM DI-159
11	HT1	Pink-Blue (P-L)	O2 sensor B1S1 heater drive	engine	Keep	EWD p.76; RM DI-159
12			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
13	PTNK	Yellow-Black (Y-B)	Vapor pressure sensor signal	engine	Keep	EWD p.75; RM DI-160
14			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
15			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
16	E1	Brown (BR)	ECM signal ground to EC	engine	Keep	EWD p.77, 121; RM DI-158

E12

ECM connector D (E12), 28-pin, body side

6 To 88 plugs 7 Remove 15 Empty

CLIP · TOP

1LLight greenRemove

2

3

4

5ACTBlue-BlackRemove

6OD2Blue-OrangeRemove

7OD1Brown-YellowRemove

8SILWhiteTo 88 plugs

9

102Violet-RedRemove

key

11IDLOYellow-GreenRemove

key

12SP1Green-OrangeTo 88 plugs

13

14BATTBlue-RedTo 88 plugs

15RRed-YellowRemove

16AC1Blue-YellowTo 88 plugs

17

18

19

20

21

22

23+BWhite-BlueTo 88 plugs

24BKGreen-WhiteTo 88 plugs

notch

25

26

27

28

Drawn as you hold the harness plug, looking into its open end, clip on top (the mirror of Toyota's DI-158 drawing of the ECM).

Every cavity (28)

Pin	Name	Wire	What it does	Group	Do	Source
1	L	Light green (LG)	A/T P/N switch 'L' position input	A/T only	Remove	EWD p.121; RM DI-284
2			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
3			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
4			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
5	ACT	Blue-Black (L-B)	A/C amplifier ACT (A/C on signal) via IJ1-1 Skipped 2026-10-12: not needed (forum swaps run without it; AC1 relay does idle-up).	body/dash	Remove	EWD p.77, 235; RM DI-159
6	OD2	Blue-Orange (L-O)	O/D main switch	A/T only	Remove	EWD p.121; RM DI-284
7	OD1	Brown-Yellow (BR-Y)	O/D cut from cruise ECU	cruise	Remove	EWD p.120, 138; RM DI-284
8	SIL	White (W)	OBD-II serial data to DLC3-7 (shielded)	body/dash	To 88 plugs	EWD p.77; RM DI-160 says R-Y
9			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
10	2	Violet-Red (V-R)	A/T P/N switch '2' position input	A/T only	Remove	EWD p.121; RM DI-284
11	IDLO	Yellow-Green (Y-G)	Idle signal to cruise ECU	cruise	Remove	EWD p.77, 138
12	SP1	Green-Orange (G-O)	Vehicle speed signal from combination meter 88 has a cable speedo; speed source UNVERIFIED (else P0500).	body/dash	To 88 plugs	EWD p.76, 121, 138; RM DI-159 (symbol SPD)
13			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
14	BATT	Blue-Red (L-R)	Constant battery (ECM memory) from 15A EFI	body/dash	To 88 plugs	EWD p.75, 120; RM DI-158 says B-W
15	R	Red-Yellow (R-Y)	A/T P/N switch 'R' position input	A/T only	Remove	EWD p.121; RM DI-284
16	AC1	Blue-Yellow (L-Y)	A/C on -> ECM idle-up request (active-low: below 2.0 V with A/C on at idle, 9-14 V off). Corrected 2026-10-12 (was labelled A/C cut) 88 swap: small relay, coil from the clutch feed (block C), contact grounds E12-16. Without it the idle sags to ~500 with the A/C on (research N).	body/dash	To 88 plugs	EWD p.77, 235; RM DI-159; RM580U DI terminals; research N
17			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
18			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
19			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
20			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
21			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
22			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
23	+B	White-Blue (W-L)	Switched +B from EFI relay	body/dash	To 88 plugs	EWD p.75, 120; RM DI-158
24	BK	Green-White (G-W)	Stop light switch signal (RM symbol STP)	body/dash	To 88 plugs	EWD p.75, 120; RM DI-160
25			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
26			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
27			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284
28			Not used No terminal shown for this cavity in any EWD319U circuit or in RM580U DI-158..160 / DI-284. Probably unpopulated; confirm on the harness.	empty	Empty	EWD p.74-77, 120-122, 138, 164, 235; RM DI-158..160, DI-284

II1

Engine wire to cowl wire joint, dark gray, 10-position (cavity 3 blanked), on the glove box

2 To 88 plugs 7 Remove 1 Empty

CLIP · TOP

1NBlack-RedRemove

2W (MIL)VioletTo 88 plugs

3

4ECT (S2)Light greenRemove

5OP3Black-YellowRemove

6STABlack-WhiteTo 88 plugs

7WABlack-BlueRemove

8W (ABS)Red-BlueRemove

9TSRed-YellowRemove

10DWhite-RedRemove

Drawn as Toyota's EWD p.41 shows the engine-wire half (female), looking into its open end. The cowl-side half (male) is its mirror image, so its numbers run the other way.

Every cavity (10)

Pin	Name	Wire	What it does	Group	Do	Source
1	N	Black-Red (B-R)	A/T P/N switch NL -> meter 'N' indicator	A/T only	Remove	EWD p.122
2	W (MIL)	Violet (V)	Check engine lamp: ECM E11-3 -> meter C11-4	body/dash	To 88 plugs	EWD p.76
3			No cavity: drawn 'X' (blanked) on both halves	empty	Empty	EWD p.41 face drawing
4	ECT (S2)	Light green (LG)	ECM S2 (E9-17) -> cruise ECU 'ECT' (A/T w/ cruise)	cruise	Remove	EWD p.120, 138
5	OP3	Black-Yellow (B-Y)	10A GAUGE -> DLC1 OP3 (cruise diag)	cruise	Remove	EWD p.138
6	STA	Black-White (B-W)	Starter signal: starter relay/clutch start circuit -> ECM STA E9-13 (A/T: also P1-5)	engine	To 88 plugs	EWD p.62-63, 74-75
7	WA	Black-Blue (B-L)	ABS ECU WA -> DLC1-22	ABS	Remove	EWD p.149
8	W (ABS)	Red-Blue (R-L)	ABS relay W terminal (warning) -> IG1-2 / DLC1 WB	ABS	Remove	EWD p.148-149
9	TS	Red-Yellow (R-Y)	ABS ECU TS -> DLC1-16	ABS	Remove	EWD p.149
10	D	White-Red (W-R)	A/T P/N switch DL -> meter 'D' + cruise ECU D (cancel)	A/T only	Remove	EWD p.122, 138

II2

Engine wire to cowl wire joint, 7-position (cavity 1 blanked), 4WD w/ 2-4 select only

6 Remove 1 Empty

CLIP · TOP

1

key

2L4Blue-RedRemove

34WDGreen-RedRemove

4M1GreenRemove

5M2Yellow-BlackRemove

6RL1Yellow-RedRemove

7RL2PinkRemove

Drawn as Toyota's EWD p.41 shows the engine-wire half (female), looking into its open end. The cowl-side half (male) is its mirror image, so its numbers run the other way.

no photo

Every cavity (7)

Pin	Name	Wire	What it does	Group	Do	Source
1			No cavity: drawn 'X' (blanked) on both halves	empty	Empty	EWD p.41 face drawing
2	L4	Blue-Red (L-R)	Transfer L4 detect switch D4 -> 4WD ECU L4 / diff-lock ECU / ABS EXI3 / ECM L4 (w/ 2-4 select)	98 4WD/ADD	Remove	EWD p.158, 169
3	4WD	Green-Red (G-R)	Transfer 4WD detect switch D3 -> 4WD ECU 4WD	98 4WD/ADD	Remove	EWD p.158
4	M1	Green (G)	2-4 select motor T1-3 M1	98 4WD/ADD	Remove	EWD p.159
5	M2	Yellow-Black (Y-B)	2-4 select motor T1-2 M2	98 4WD/ADD	Remove	EWD p.159
6	RL1	Yellow-Red (Y-R)	2-4 select motor T1-6 position (4WD)	98 4WD/ADD	Remove	EWD p.159
7	RL2	Pink (P)	2-4 select motor T1-5 position (2WD)	98 4WD/ADD	Remove	EWD p.159

II3

Engine wire to cowl wire joint, white, 26-pin, on the glove box

10 To 88 plugs 16 Remove

CLIP · TOP

1PBlue-YellowRemove

2NSW feedBlackRemove

key

3LLight greenRemove

42Violet-RedRemove

5ABPink-BlackRemove

6PWRGreen-RedRemove

7L4Blue-RedRemove

8IG2Black-RedTo 88 plugs

key

94WD ind.Green-BlackTo 88 plugs

10GNDWhite-BlackRemove

11TFNRed-GreenRemove

12OIL-WYellowRemove

13V2 (3RZ)Gray-BlueRemove

14V2 (3RZ)Pink-BlueRemove

15TACHBlackTo 88 plugs

16+B (EFI)White-BlueTo 88 plugs

key

17ADDGreen-RedRemove

18SGBrown-RedTo 88 plugs

19Back-upRed-YellowRemove

20Gauge feedBlack-YellowRemove

21TempYellow-RedTo 88 plugs

22OilGreen-WhiteTo 88 plugs

23TCYellow-BlackRemove

key

24GND (SIL shield)BrownTo 88 plugs

25MGCLight green-BlackTo 88 plugs

26FCGreen-YellowTo 88 plugs

Drawn as Toyota's EWD p.41 shows the engine-wire half (female), looking into its open end. The cowl-side half (male) is its mirror image, so its numbers run the other way.

Every cavity (26)

Pin	Name	Wire	What it does	Group	Do	Source
1	P	Blue-Yellow (L-Y)	A/T P/N switch PL -> meter 'P' indicator	A/T only	Remove	EWD p.122, 158, 164
2	NSW feed	Black (B)	7.5A STA (ignition ST2) -> P1-6 and ECM NSW E9-14 (A/T only; M/T routes ST via cowl I1, not II3) Removing it leaves NSW open, which is what the A/T ECM needs. Never ground it.	A/T only	Remove	EWD p.62-63, 75, 120
3	L	Light green (LG)	A/T P/N switch LL -> meter 'L' + ECM L (E12-1) via I19	A/T only	Remove	EWD p.122
4	2	Violet-Red (V-R)	A/T P/N switch 2L -> meter '2' + ECM '2' (E12-10) via I19	A/T only	Remove	EWD p.122
5	AB	Pink-Black (P-B)	SRS warning line -> DLC1 AB	SRS	Remove	EWD p.156
6	PWR	Green-Red (G-R)	A/T pattern select switch -> ECM PWR (E10-12)	A/T only	Remove	EWD p.121-122
7	L4	Blue-Red (L-R)	Transfer L4 detect D4 -> diff-lock ECU 4WD / ECM L4 (trucks w/o 2-4 select)	98 4WD/ADD	Remove	EWD p.164, 169
8	IG2	Black-Red (B-R)	Ignition IG2 power -> injectors, coils, igniter +B, noise filter	body/dash	To 88 plugs	EWD p.63, 74
9	4WD ind.	Green-Black (G-B)	ADD indicator switch (ED1-2) -> meter 4WD lamp, ECM 4WD E9-1, ABS EXI ECM 4WD input (E9-1). Joins the 88 transfer 4WD switch LG (salvaged from the 3VZ harness) at junction D, with N3-1.	body/dash	To 88 plugs	EWD p.158, 164
10	GND	White-Black (W-B)	Ground for transfer switches D3/D4/D5 (-> IF)	98 4WD/ADD	Remove	EWD p.121, 159, 164
11	TFN	Red-Green (R-G)	Transfer neutral switch D5 -> meter C10-12 (A/T) and ECM TFN	A/T only	Remove	EWD p.121, 158, 164
12	OIL-W	Yellow (Y)	A/T oil temp warning lamp: ECM E11-6 -> meter	A/T only	Remove	EWD p.121-122
13	V2 (3RZ)	Gray-Blue (GR-L)	3RZ-FE only: meter vehicle speed sensor V2-3. On 5VZ the meter GR-L comes from the ABS ECU instead Strip only if a wire is present.	empty	Remove	EWD p.168 (*6 = 3RZ), p.228 (*2 = 3RZ)
14	V2 (3RZ)	Pink-Blue (P-L)	3RZ-FE only: meter vehicle speed sensor V2-2 Strip only if a wire is present.	empty	Remove	EWD p.168 (*6 = 3RZ), p.228 (*2 = 3RZ)
15	TACH	Black (B)	Igniter EXT tach signal -> combination meter tachometer Tach node (junction E): also feeds the 88 A/C amplifier's engine-speed input (amp pin 5, BLK 'IGNITER', Mitchell 5-609), via whichever N5 cavity test 4 finds (likely N5-16 B).	body/dash	To 88 plugs	EWD p.63, 77, 228
16	+B (EFI)	White-Blue (W-L)	EFI relay output -> MAF, IAC, VSVs, O2 heaters, DLC1 (+B bus)	body/dash	To 88 plugs	EWD p.74-76
17	ADD	Green-Red (G-R)	ADD control relay -> transfer 4WD detect switch D3 / ED1-1 (w/ ADD)	98 4WD/ADD	Remove	EWD p.164
18	SG	Brown-Red (BR-R)	DLC3 signal ground (pin 5) -> engine ground EC	body/dash	To 88 plugs	EWD p.77
19	Back-up	Red-Yellow (R-Y)	Back-up light switch output (A/T P/N RL, or M/T back-up switch B1) -> back-up lamps + ECM R (E12-15) Removed: the R150 reverse switch keeps its own 88 wiring (salvaged whole from the old 3VZ harness) into the salvaged N3 half (N3-2/N3-6).	body/dash	Remove	EWD p.116, 122
20	Gauge feed	Black-Yellow (B-Y)	10A GAUGE -> P/N switch RB (A/T) or M/T back-up switch B1-2 Removed: the R150 reverse switch keeps its own 88 wiring (salvaged whole from the old 3VZ harness) into the salvaged N3 half (N3-2/N3-6).	body/dash	Remove	EWD p.116, 122, 138
21	Temp	Yellow-Red (Y-R)	Water temp sender W2 -> meter temp gauge Kept 2026-10-12: II3-21 -> 88 N3-7; 88 temp sender screwed into the 5VZ port on this wire (swap the end terminal/housing if the 98 plug does not fit).	body/dash	To 88 plugs	EWD p.228
22	Oil	Green-White (G-W)	Oil pressure switch O1 -> meter oil lamp Kept 2026-10-12: II3-22 -> 88 N3-8; 88 pulse oil sender on this wire in place of the 98 switch (swap the end terminal/housing if needed).	body/dash	To 88 plugs	EWD p.228
23	TC	Yellow-Black (Y-B)	DLC1 TC -> J3 -> ABS TC / SRS TC / cruise TC	body/dash	Remove	EWD p.138, 149, 156
24	GND (SIL shield)	Brown (BR)	DLC3 SIL shield drain (I18) -> engine ground EC	body/dash	To 88 plugs	EWD p.77
25	MGC	Light green-Black (LG-B)	A/C amplifier MGC -> A/C magnetic clutch A2	body/dash	To 88 plugs	EWD p.235
26	FC	Green-Yellow (G-Y)	ECM FC (E10-18) -> circuit opening relay coil	engine	To 88 plugs	EWD p.74-75

Source data: swap-wiring/research/pins98.json and L-98-plug-pins.md. Regenerate: python3 -I swap-wiring/tools/build_98_diagram.py.

Strip list

Rule (2026-10-12): keep only what an 88 4Runner with its original manual transmission plus the 98 5VZ with a 98 manual-transmission ECM would use. Every other wire: de-pin it and remove it. Cavity-by-cavity: print/98-connector-diagram.html (Strip & keep view). The 88 transmission switches (R150 reverse, transfer 4WD) keep their whole original 88 wiring, salvaged from the old 3VZ harness and re-pinned only at the adapter end; the 98's ED1 and II3-19/20 versions are removed.

Goal: only the wires the 88 4Runner 3VZ-E with the R150 needs. Pins come from EWD319U p.74–77, 120–122, 158–164.

Decisions this is based on: keep the 98 A/T ECM for now (A/T codes and MIL accepted). No A/C cut-out. Keep the 88 dash, HVAC and A/C amp.

How to remove things (so it stays reversible for the aftermarket ECU)

• At the ECM and II plugs: de-pin (pull the terminal out with a pick), tape each terminal by itself, and fold it back. Don't cut at the plug.
• Whole branches (A/T, transfer): unwrap the harness back to where the branch leaves the trunk, cut there, solder or heat-shrink caps, re-tape.
• Dead wires that stay inside the trunk are harmless. Don't unwrap the whole harness to chase them.
• ⚠ Shared splices: three of the branches below share a splice with wires you're keeping. Cut on the branch side of the splice only.

1. Remove whole branches from the 98 engine harness

2. De-pin at the ECM (E9/E10/E11 stay plugged in)

E9-2 (L4) · E9-11 (S1) · E9-14 (NSW) · E9-17 (S2) · E9-27 (SL) · E9-30 (ATF temp) · E9-31 (PSW) · E10-4 / E10-9 (SP2−/+) · E10-12 (PWR) · E11-6 (OIL-W) · E11-9 (TFN)

Keep E9-1 (4WD). It's fed by the 88 4WD switch, below.

3. E12 (body pigtail): keep 6, remove 7

• Keep: 8 SIL W · 16 AC1 L-Y (idle-up relay) · 12 SPD G-O · 14 BATT L-R · 23 +B W-L · 24 STP G-W
• Remove: 1 · 5 (ACT, skipped) · 6 · 7 · 10 · 11 · 15

4. II joint (engine-to-cowl, glove box)

• II2: delete the whole connector (2-4 select / 4WD ECU).
• II1, keep 2: 2 V (CEL) · 6 B-W (STA). De-pin 1, 3, 4, 5, 7, 8, 9, 10.
• II3, keep 10: 8 B-R IG2 · 9 G-B 4WD light · 15 B tach · 16 W-L +B bus · 18 BR-R DLC3 SG · 21 Y-R temp · 22 G-W oil · 24 BR shield ground · 25 LG-B A/C clutch · 26 G-Y FC.

De-pin 1–7, 10–14, 17, 19, 20, 23.

• Direct plug-in (2026-10-18): the kept II1/II3 wires are de-pinned and pinned (with new 88-type terminals) straight into the N3/N5 halves cut from the old 3VZ harness. II1/II2/II3 end up empty; keep the housings. II3-24 (shield) is only needed as the DLC3 data-cable drain, grounded at one end. Cavity-to-cavity list: adapter-build-list.md.

5. Kept on the engine side (no change, just make sure they're plugged in)

• Fuel and spark: injectors 1–6, coils 1–3, igniter.
• Sensors: cam, crank, MAF, TPS, IAC, ECT (EC1), knock 1 & 2 (EB1). (PS pressure switch P22 removed 2026-10-19, see section 1.)
• Senders: 98 harness wires II3-21 (temp) and II3-22 (oil), with the 88 temp sender and 88 pulse oil sender on their ends (swap the sender-end terminal/housing for the 88 one if the 98 plug won't fit).
• O2 sensors: B1S1 and B1S2. The exhaust needs a bung after the cat for S2, or you'll get O2 codes.
• EVAP: VSV, vapor-pressure VSV and vapor pressure sensor. Leave them plugged in and mounted to avoid circuit codes; leak-monitor codes are possible without the 98 canister.
• Other: A/C clutch, EC ground eyelets, DLC1 diagnosis box (kept 2026-10-21, for the TE1/E1 timing check and a stock-ECU fallback).

6. New wires and parts (direct plug-in, 2026-10-18)

What's left in the finished harness

• N3/N5 halves: 11 98 wires moved, 6 new E12 wires, 5 junctions, 4 salvaged 88 wires (2 reverse, 4WD LG, new 4WD W-B).
• DLC3: the 98 pigtail (4 leads).
• New parts: 2 relays, 1 kill switch, fuses.
• MIL: stays on for A/T codes until the aftermarket ECU (decision from 2026-10-07). Use an OBD-II reader to watch for real engine codes.

The five wiring sheets

Redrawn for direct plug-in on 2026-10-18. Where these sheets differ from the sections above, follow the sections above.