When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I have a 77 c3 that my interior lights are staying on all of a sudden. They worked great until I pulled it out to check and make sure everything was working correctly and after opening driver door a couple of times the lights are staying on now. Any suggestions as to what to look for?
My apologies I forgot to mention that I have replaced headlight switch and have turned the **** with a glitch in the lighting and I have also pulled the jamb switch out to inspect it on both sides. I have 3 wires on driver side and 2 on passenger side. I had a significant draw on my battery before this and narrowed it down to factory alarm so I unplugged the alarm relay to solve that issue and everything was working fine then the first time I pulled it out and open and shut driver door a couple of times it stays on.
is it possible the door pin switch was incorrectly wired? Pull the pin switch back out one at a time and see what happens. It sounds like the pin switch ground is connected to the courtesy circuit and as a result its always grounded, thus completing the circuit, whether the door is open or closed
I put a mark on the connector before I pulled it apart and there was a little corrosion on one pin so I scuffed it up still no change. I disconnected both switches and put fuse back in and still have lights.
If both switches are disconnected and the lights are still on...Just to start with the most obvious...are you sure that the headlight switch isn't turned all the way to the left so that the lights will come on. You wouldn't be the first to have that issue. Beautiful car BTW..
the door switch might just need an adjustment. Screw it out towards the door frame. Not sure which one so check both doors.
I could certainly be wrong about the courtesy switches on '77s, but aren't these switches self-adjusting when initially installed? I believe the cylinder around the nut is an interference fit such that it will slide inward when the door is first closed, creating the proper spacing. If the cylinder has been pushed in too far from other causes I think it can be reset by extending the cylinder from the nut and closing the door again.
Originally Posted by ZIOGEO
is it possible the door pin switch was incorrectly wired? Pull the pin switch back out one at a time and see what happens. It sounds like the pin switch ground is connected to the courtesy circuit and as a result its always grounded, thus completing the circuit, whether the door is open or closed
Again, could be wrong, but there's not much wiring error that can occur with these. Each system (lighting, alarm, door ajar(?)) has a single terminal that, when the door is opened and the plunger contacts the nut body, connects to ground (birdcage/body mount frame).
I have a 77 c3 that my interior lights are staying on all of a sudden. They worked great until I pulled it out to check and make sure everything was working correctly and after opening driver door a couple of times the lights are staying on now. Any suggestions as to what to look for?
Does your 77 have the convenience group option?
If so it's possible your curtsey light delay timer "May" have failed in the closed position
With both door switches disconnected the lights are still on and when I turn the light switch to the left as to turn on interior lights I get a little glitch. I’ll try to locate the light delay or any idea where it is located? Thanks so much for everyone’s help and advice.
The delay timer is taped to the main dash harness between the speedometer & tachometer (if not messed with in the past)
Here is a drawing, the lower drawing is the 2 connectors that were disconnected (and timer installed between them) IF the delay was installed.
If you reconnect those to connectors you have bypassed the delay timer.
So with the door switches disconnected the lights remain on?
Im thinking your headlight switch is defective. The courtesy lights have 12 volts on one side at all times and then when either door is opened, the switch completes the circuit by grounding the other side of the bulb. With both door switches removed then at that point the only place the circuit can find ground is back at the headlight switch. This is according to the wiring diagram I have for a 77.
Im looking for a diagram on the courtesy delay circuit but havent found one. If anyone has it please post it.
The right diagram on this drawing for the 77 with delay.
With the delay circuit, the reason the lights stay on at ALL with the door(s) closed is primary ground is found at the eyelet on the above AIM drawing and is labeled G901 on the drawing below black arrow. G901 through the timer is what keeps the lights on after door(s) are closed until heater cools down and then the contacts return to the N/O position...
The red arrows C121 (C=connector) are part of the main dash harness.
One connector has two (2) white wires and the other connector has one (1) white wire.
Simply disconnect those two connectors from the delay timer and plug them in together, this bypasses the timer and returns the circuit to the drawing on the left...
Ok, this makes total sense. I imagine the replacements for the light timer are 555 based.
So this was only on cars that were optioned for it?
Correct, in 78 they changed to a transistor style timer...
Willcox Corvette used to sell a direct replacement timer by I'm not sure they are still available.
Ok. So its either a failed delay timer or a defective headlight switch. At this point it can only be one of those two things. Hopefully the OP can sort this out from here.
Thanks for posting the diagram bmotojoe
Interior lighting
😉🤣😉🤣❤️
