Ωhm

brake system_Brake height sensing valve.pdf

More FYI stuff. @coheed

Make sure all your heavy cables make good clean contact. Battery(+) to Solenoid, Solenoid to Starter and Engine Block to Battery(-). Check Starter bolts, make sure there not loose.

Taken from REM Codes Description on NICKs website. ECU Codes These codes come from the 4.0L ECU’s internal Power On Self Test mode. They only run once when the key is turned from Off to Run and can be a little unreliable. No Injector 12V ECU did not detect 12V on Injector feed wire. -TIP: If this code shows with “KO Tests Not Run,” it can be ignored.

Connect DVOM across the ballast resistor with both Fuel Pump connectors connected. Polarity doesn't matter (+/-), just looking for the number (vdc). CRANK engine. Should read between 3-4vdc.

Yeah. With bulkhead disconnected, it's got to be under the dash. Fuse/Circuit Breaker question. If CB trips faster might be the way to go. I don't know if I like that CB, but you try another one before and the new one still got hot. With bulkhead disconnected you might have to go straight to the battery for voltage source. Keep in mind wire size. We're dealing with a 30A_CB or 25A_fuse. Don't want to turn the jumper wire into a fusible link.

As far as I can tell, problem circuit is both, under the hood or under the dash. With bulkhead separated and backfeeding the fuse could prove out 'under the dash' as GOOD or BAD. Lets hope the 25 amp fuse never blows and this problem just goes away. Wishful thinking here.

Is the CB in the same place as the Blower Fuse would be? If yes, disconnect the Horn Relay (C192). With connector disconnected apply 12vdc (fused jumper) to C192_B. IGN_SW key must be in the OFF position, otherwise you'll be backfeeding the IGN_SW itself. Also, make sure bulkhead connector is separated.

With bulkhead connector disconnected, does the Circuit Breaker (CB) still get hot? EDIT: Disregard, No Ignition SW, but with a long enough jumper you could backfeed that CB.

Excess current flow, shorts to ground will cause heat but so will a voltage drop at the breaker itself. What I'm wondering is do you have a faulty circuit breaker.

I'm using the 1988 Electrical Manual. They claim its close, but maybe it not. _mj1988electricalmanual_1.pdf Page_36 shows Splice_B and page_87 shows location of Splice_B. This splice will appear with the letter (B) within a circle. Look at lower left hand of page_87. Odd I can't find any 4_pin connector. yet. AC Clutch Relay C241 is shown on page_87. If AC low pressure SW is disconnected and it still gets HOT, problem lies between this C239 and C236_A.

No leave the circuit OPEN (disconnected). If it still gets HOT, problem lies between C239 (AC low pressure SW) and C236 (AC Mode Select SW). This could mean the AC controller itself, but you mentioned you rebuild that. Yes. Do a wiggle test. The function will not matter as to which way the connector is connected. But one side goes to the AC Mode Select SW and the other side feeds Splice_B. If all looks good, wiggle test the Splice_B side of the harness.

I never guessed using the Ω as part of my password would cause these kinds of problems. Need to turn NUM LOCK on.

Remove that jumper wire installed on the AC low pressure switch (C239). Determine if problem still exist when AC is engaged. If so, problem exist between C239_2 and Blower Motor fuse (circuit breaker).

Each bulb in each red lens compartment is a two (2) filament bulb. One filament of each bulb is for tail light circuit, the other filament is shared between the turn signal and the brake light. The turn signal switch (steering wheel) determines which function it will be, a turn signal circuit or a brake light circuit.

Backprobe AC Mode SW (C236). Backprobe connector C236_D (VIO/YEL) using voltmeter or testlight. Connect other end to good ground. Look for voltage drop out when problem occurs.

I've noticed that things in life only get better.

Spaghetti wiring mess.

Off Topic: ECU pin C200_8 served two different purposes for different years, 1986 used it as a Wide-Open Throttle SW (WOT) while 1988 use it as a Power Steering Pressure SW (PSPS). I would hope the ECUs have different part numbers. Could affect drivability.

Thanks. Noted on my picture directory.