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If you don't have the Cargo Lamp Switch, harness should still have the connector (C366). If you don't have the Fog Lamp Switch , harness should still have the connector (C176). Look under dash left side. Problem is both C176 and C366 are identical (look alike). Both use Pin_A for ground and Pin_B for B+. C366 is hot when PARK lamps are lit, C176 is hot when HEADLAMPS are lit. If you have both available, you'll need to determine which is which.

Incandescent bulbs or LEDs? Dash lights work off the DIM circuit of the Headlight Switch and and can be dimmed.

Check out Cruisers Tips 11 & 14. http://cruiser54.com/

B+ Latch Relay is acting as designed.

Check B+ Latch Relay. Connect DVOM or testlight to D2-5. When KEY is cycled ON should have B+. When KEY is cycled OFF, should hold B+ for a few seconds afterwards. Does fuel pressure drop to 31psi at idle?

Any luck on downloading the Electrical Manual?

Click on your username (upper righthand corner). Click on Account Setting. Under Overview, click on Signature. Add your Year and Engine and anything else about your vehicle. Press Save.

88 Electrical Manual Click on and download the above link. Once downloaded, open file (.pdf). We need to get on the same page.

Yes WOW! What a mess, both under dash and under hood, I hope you live next door to a fire station. Which of the cavities are in use on C236? Your wiring might go 'beyond me and my keyboard'. Also with C235 disconnected, that's trying to tell you something. Follow them wires.

Disconnect C236 at the AC Mode Select Switch (climate control panel) and leave it disconnected. Determine if Blower Fuse still blows. You may have to drive vehicle around for a while, since fuse fails to blow instantly.

Just re-read your first post.

Not going to tell you not to swap out the CTS(ECT) sensor, but if engine was at normal operating temperature, 199° seems like a valid reading. Too bad on no TESTER being around. Would've liked watching FT for awhile. Your STFT reading shows INJ PW (4.6mS) going LEAN. If this is true, suggest the following: Fuel rail pressure could be HIGH. Check vacuum hose from manifold to fuel pressure regulator. Connect fuel pressure gauge. With engine running look for 31psi at idle and 39psi with vacuum hose removed/plugged and engine running. Make sure fuel rail hold pressure for at least 30 minutes (leaky injector(s)).

When O2S heats up (O2 Heater) and starts rapidly switching (RICH/LEAN), ECU should go into CLOSED LOOP. Not sure how TESTER calculates Throttle(%) or TPS(V), could be normal readings, but the TESTER should display only what the ECU sees. You did recheck values with a DVOM? Does the parameter for EXHAUST switch for RICH to LEAN quickly?

STFT (45) shows engine running RICH, engine is in closed loop, so ECU is within its range of authority. That means good. Look into Throttle(%)/Throttle(v), readings seem low. Faulty ECU or faulty TESTER, man tough call there.

It's a 8 slotted grill, if that matters.