Khibbs

So I'm digging into my newly acquired 1981 which is a solid car but has some electrical gremlins. I knew this going in and would rather chase bad grounds then do bodywork any day.

I have the Haynes manual and was able to a wiring diagram from papawana...thank you!

I've started to pull up the center console to replace some light bulbs and check on a few things. I found there was a little rodent who was hiding in there as the car wasn't driven for a number of years.

Can anyone help identify what these wires are. They come out of a harness, there is a plug (Dk Blue, Lt Blue, Yellow, Black or Brown) right behind the parking brake handle, and then go back into the rear harness that goes to the driver's side. I can't seem to find it on the wiring diagram for some reason.




Oh.. and I'm trying to get my power locks working. Does anyone know what fuse they run off of? All mine look good but I figured I'd start there and then chase wires / grounds.

Thanks!

Grahamred70

A bit of a rats nest there in more ways than one! I'd be running a meter over all the electrics once you've made repairs to be sure before thinking about connecting up a battery, I've seen insulation stripped before but not seen wires eaten right through before, scary stuff!
Good luck with that one, I had similar issues but it was down to Bubba cutting wires instead of fixing the problems!
Graham

Khibbs

Thanks Graham. The car is running fine and I'm down to a few last electrical items so I'm past hooking up the batt although good advice if I'd seen these earlier.

Its down to power locks, pass power window, and tach. Everything else is now up and running which is strange since these are running to the back of the car. I have to dig in deeper tonight but if it's 4 wires I'm wondering if they could they have been for rear speakers?

jim-81

I don't have an answer to your question except that if you can get a hold of the shop service manual, this has all the electrical circuits in it COLOR CODED. It's very nice and easy to work with. Definitely recommended. You could probably find one on ebay or in the for sale section.
Jim

Antz81

The connector with the four wires is for the rear speakers. But I would have more concern about the other wires that can be seen in that picture.

The power locks run off the ctsy/clk fuse (20A), there's a few things that run off this fuse so if the lock are the only thing not working I'd say the fuse is fine. Check both switches, if there is a problem with one then the locks won't work.

SwampeastMike

That connector has the proper color wires for the rear speakers.

I suspect that red wire with "CAROL" written on it is not original. Red wires in GMs of our vintage are +12V main (before fuses) power lines. There will not be any red wires in the cabin harness.

Regarding your driver window: I suggest connecting it to the working passenger window switch. If it now works you know that the problem is the switch itself. Search here for an article by Willcox that details how to disassemble and repair a power window switch. If it doesn't work when attached to the other switch the problem is in the wiring or the motor itself. To determine which remove the door trim panel and the motor/window access panel. "Hot wire" the motor to see if it runs. If it does you've got a wiring problem.

The power locks are on the CTSY circuit. Every solid orange wire you find in the cabin is +12V constant power from the CTSY fuse. The CTSY circuit also operates the power antenna, cabin lights, alarm system, cigar lighter and probably a couple other things I forgot... The connectors to the power lock switches are known for falling apart. Pigtails with a new connectors are available from the vendors. None of the power lock wiring is in the cabin harness branch that goes back through the console. The locks get their ground from a connection in the passenger door.

Khibbs

Thanks for the replies!!

Antz81 - Thanks for the confirmation on the rear speaker wires. That makes a lot of sense and I'll double check but I don't think they are listed on the wiring diagram I have.

The other wires in the background are not factory and for an amp that was installed and is coming out so I'm good there. I've inspected everywhere else for sighs of intruders and I think I'm in the clear.

SwameastMike - The power windows are working (although the pass side is REALLY SLOW) it the power locks that are not working. I'll check power to the switch and then trace it out from there. I'm wondering if it might be a bad ground somewhere.

Speaking of the cabin lights, they are constantly on even with the doors closed so the PO removed the bulbs. I removed and cleaned the door switches which didn't help so I need to do a bit more work to trace out those wires.

Antz81

The window may just need a bit of ckeaning and lubrication.

For the lights check that the bypass on the light switch isn't on. Just rotate the ****, if you feel a click and they don't go out then it will most likely be the delay module behind the glove box, unplug it and they should go out. If not you have a ground fault.

Khibbs

Thanks Antz81 .... I totally forgot about rotating the light switch for the bypass. I'll try that and then head to the delay module next.

I'll report back.

Here is the main thread for the car.

SwampeastMike

If the window is slow to rise but fast to lower then the assist spring is probably broken--a VERY common problem. If the window is slow in both directions there is some other problem. It's possible that the black bumpers you'll see at the top of the door (you have to remove the door trim panel) are adjusted too far outboard and putting to much pressure on the glass. If this is the case such is likely because another window adjustment is off and this was done to compensate. If the adjustments are all OK it is likely a matter of gummed up tracks and/or worn/broken rollers. Working inside C3 doors isn't an awful job but it's not the sort of thing you want to do more than once... When removing the tracks to clean and re-lubricate (removal is the only way to do this) check EVERY window related component carefully and replace anything that is broken or "iffy". It's also a good time to remove, clean and re-lubricate the rather complicated door lock mechanism as they too gum up which stresses the actuators.

Regarding the power locks: There is only one ground--it's in the passenger door and you'll see it bolted to the inner metal. If your locks are difficult to operation manually the only problem may be the need of cleaning and lubrication--this too is quite common but don't be surprised if the actuator itself has gummed up and doesn't have the "umph" to fully move even a perfectly operating mechanism. If you short-cut and lube the lock mechanism without removal be careful not to get spray lube on the inside of the fiberglass surface. According to an expert here such can eventually cause problems with the paint. Again, it's best to disassemble, remove, clean, re-lubricate and reassemble in that order.

To see if the delay module is causing problems first disconnect the module. Then jump the two white wires on the harness connector. The lights should now work like normal--open door(s) = lights on; closed doors = lights immediately off. If the lights are still on there is a short to ground somewhere in the courtesy light circuit. The lights all have constant +12V via the CTSY fuse (a solid orange wire). Either door switch, the headlamp switch and the delay module can all provide a path to ground allowing them to light.

Black wires are always chassis (permanent) ground. Solid white wires (and usually white wires with stripes) are switched grounds such as in the courtesy light circuit.

Khibbs

SwampEastMike - Thanks SO much for this detailed info. I only got a few minutes with the car this weekend but was able to pull the glove box before other duties pulled me away.

I found an orange box behind it which I assume was the delay module. I saw white wires on either side of the plug that goes into it. I've pulled the plug from the module and will try a jumper across them (with the plug removed) tonight and see if that's the problem or I need to start looking for grounds.

Thanks again for your help and I'll report back tonight.

Khibbs

So I found the delay module behind the glove box and as soon as I disconected the plug the done light goes out. I connected a jumper wire across the two WHITE wires and the light came back on but didn't go out when I closed the door.





It sounds like this would mean that it's not an issue with the delay module. Where should I start looking next? I'd love to find and clean/inspect all the grounds I can but I'm not sure where they're all located.

SwampeastMike

It's not a matter of dirty/poor ground--it is a short to ground on the white wire.

Your symptom (jumping the wires at the delay connector caused the lights to come on with both doors closed) greatly narrowed the possible location for that short--it somewhere in the door switch portion of the circuit that goes to both switches and the delay module.

I'd first check the door switches themselves. Once removed and manually operated you'll instantly understand how they work. Be certain that they are properly adjusted, functioning and that the contacts/connectors aren't shorting against the frame. They simply unscrew--a deep well socket is by far the best too to use.

Khibbs

A quick update.... I was able to wrap my little brain around how the circuit actually works after I pulled both switches out again and cleaned them up a bit.

Driver Side:



Passenger Side:



I couldn't get the light to go OFF not matter what I did. I had them both out and it was still on so knew it wasn't being grounded via the switches... hmmmm

Then I stopped and remember that the light went off when I pulled the plug from the delay module and it came back on when I jumped the two white wires BUT I never tested the door switches with it jumped for proper operation.....



The door light goes on/off with the doors now so I'll order a new delay module board from Wilcox.

Thanks for your initial guidance SwampeastMike and others and I need to go slow and make sure I'm paying attention to all these good instructions.

I'm on to the power locks next!

SwampeastMike

Glad you identified the problem! I thought you said that the lights stayed on with the jumper installed and the doors closed.

One reason that the delay modules fail is if a door is left open for an extended period. One of the transistors overheats and when it fails the lights will never go off.

Before you suspect wiring, switches, etc. as the problem with your locks be certain that the mechanisms aren't just gummed up enough to prevent the actuator from moving sufficiently. When new to me my '79 had the same problem and while not particularly fun all it took was removal, cleaning, lubrication and re-installation to get them working nicely. As I suggested before such is also the time to do the same with the window mechanisms.

Khibbs

Ok, that makes sense on the delay module. I'll hope in the replacement board they've resolved that issue otherwise I'd go for the by-pass board.

Thanks for the advice on the locks. The pass window barely goes up so I know I'm going to have to pull that do panel at the least so I'll start there and report back.

Thanks again!

Kent

SwampeastMike

I'm not sure if the burn-out problem has been addressed but I read that such only occurred a door open for hours or a bad jamb switch. My [presumably] original module shows some sign of overheating (discoloration of the circuit board) near one of the transistors but it still works fine.

Do some searching here for a photo that shows an installed window mechanism from the outside with the door skin removed. Such was the single most helpful thing I found to understand how everything went together. I studied it carefully BEFORE disassembly as the instructions and illustrations in the factory service and assembly manuals still left me scratching my head.

Khibbs

Mike - The replacement board arrived yesterday and I was all excited to plug it in and be on to the next puzzle. I jumped in the pass side, closed the door and as soon as I plugged it in the interior lights came on......

I opened and closed the door, checked the connections to the module, and it's the same issue. The lights are on all the time.

Since I was able to get them to operate as they should with the white wire jumped what do you think could be the issue??

Thanks - Khibbs

Antz81

how long did you wait for the lights to turn off? Mine can take a couple of minutes

Khibbs

I didn't think of that but I must have waited 30 seconds. I'll plug in in again tonight and double check. Your lights can really stay on for a few minutes after you close the door? That seems like a long time.