Hopefully somebody else has run into this stuff and can help me solve it.

I went ahead and put the 1994.5 harness back in and hooked everything up. The engine starts from the keyswitch and seems to run fine. The oil pressure and temp gauges appear to be working properly.

The ammeter/voltmeter doesn't work at all, and neither does the tachometer. Did I miss a connection somewhere?

The turn signal indicator lamps in the dash come on with the key in on or run, and stay on. They blink with the turn signals like they should, but otherwise they're on all the time. I don't know why.

The headlights and taillights work, but the floor dimmer switch does nothing. None of the dash lights work.

Can anybody shed some light on what's going on with this stuff?

 

Floor dimmer switch? In a '94.5?

 

Yeah. I wasn't paying attention to these details. It's a 1991 truck converted to 1994.5 drivetrain and harness, so the floor dimmer is still present, even though it isn't connected to anything. I need to remove it, was planning on doing that today.

The multi-function switch on the steering column controls the brights and wipers and turn signals etc. I just wasn't really thinking about that when I started diagnosing the electrical problems we're having.

 

Okay, got it figured out. I think. Turns out, the two ground wires on the passenger side aren't the main ground wires for the system. In fact, most of the dash does not ground through those at all. Only the stock radio plugs, what I think is the ABS control box, and part of the instrument cluster ground out through those plugs.

The rest of the harness grounds down through... something else. I have identified a wire I can use as my primary ground. I do not know if that's what it was supposed to be or not, as it's been cut off. But that's what I'm going to use it for.

I have to take care of some other business tomorrow, but I should be back on task Thursday to get this thing put back together and see if I'm right. If I am, all the dash stuff should start working properly, the lights should all work right, the wipers and heater should all work correctly, and even the power windows will start working again.

then I can start looking into why the engine won't start now. Hopefully that's something simple too.