Automatic Door Lock Problem HISSIN?

[revhead347]

I've run into an electrical problem on the 94' Cobra that is mysterious. The left hand power door lock switch doesn't unlock the doors. We swapped the door lock switches, and tried new ones, and it doesn't matter. The problem is in the wiring, not the switch. I checked the wiring diagram, and the unlock circuit is a simple joined circuit that goes to the keyless control module. I checked the continuity between the left unlock circuit, and the right unlock circuit, and there seems to be good continuity. I'm not getting any resistance across the circuit. I checked the contact on the left door lock switch, and from a visual standpoint, the contact seems good. Does anyone has any ideas where the problem could be? HISSIN?

Kurt

 

[HISSIN50]

As you know, this stuff is a pain Kurt.

Does the passenger switch function properly when used from the passenger side? I assumed so, but we know where assumptions lead.

Does the car have factory or aftermarket keyless? Does the keyless remote allow the locks to function properly?

I'm sure you've programmed spare factory fobs before (grounding the keyless module in the trunk) Kurt. If he does not have a factory fob, I'd almost spend a minute and do that with your or a spare fob to see what happens.

If he has an aftermarket keyless or alarm, did it function properly at some point (some installers hack the wiring)? Someone might have used a couple of relays instead of a 451M and the unlock relay might have gone bad or broke a connection on the relay output.

If you're checking wiring, many installers grab the lock wires in the rocker panel (remove the door sill trim [that long plastic runner] and the wires are under the carpet). You might see some wire taps in there................

 

[revhead347]

The car has a factory keyless entry, and no aftermarket alarm. The next step is to start tracing wires, but nothing like that has ever been installed on the car, so whatever has failed has been from natural causes. A door lock switch installed in the passenger side works properly. The same switch transferred to the driver's side will lock the doors, but not unlock them. The factory keyless entry fobs work on all functions. It's just that one circuit from the driver's side door that isn't working.

Kurt

 

[HISSIN50]

I gotcha now. Worst case, I don't see why you could not run a new wire from the switch that connects to the factory wiring in the rocker panel (just bypass the problem area).

 

[revhead347]

I gotcha now. Worst case, I don't see why you could not run a new wire from the switch that connects to the factory wiring in the rocker panel (just bypass the problem area).

Yeah, realistically that wire has to be pinched somewhere. The ohm meter doesn't run much current through it, and is not a good indication. I'm just not looking forward to pulling apart that whole wiring harness inside the door.

Kurt

 

[HISSIN50]

You said you had good continuity. I figured you also probably checked continuity to ground while testing (in case of a S-T-G).

Anyhoo, that's why I'd just run another wire - it's pretty easy to do on these cars (easier than a fox III).