ezrider01

Okay, So my next issue is having to do with the courtesy / dome light. 1977.

I have replaced all harnesses of the car throughout so I am working with new harnesses.

So when I was working out some other electrical bugs, I came across the issue where both my courtesy and dome lights do not shut off with the door switches pressed. Interior cabin switch has no affect either. Door switches are also new and ground seems to be good. Door switches actually have no effect as I can disconnect the door switch and the lights still stay on????

So my application has the 3-prong d/s door switch and a 2-prong passenger s/d switch.

A buddy of mine was suggesting that it could be the headlight main switch that is causing the constant 12V to the door switch line.

Has anyone ever encountered this issue and what did you do to correct it?

Any Ideas to help troubleshoot this issue is deeply appreciated.

vetteguy75

I had the very same thing happen this weekend to my 75 Vert. I had replaced the driver side socket with a single wire, single-pole socket made for the interior light (not Corvette). Whenever I closed the doors, the light would stay on. I couldn't understand WHY. Anyway I had to have my mechanic/friend come over and fix it for me. He said something about the ground of the new socket was wrong. Not sure what he meant....I was excited he fixed it for me.

I'll contact him at the dealership, in the morning & ask him specifically what he did and I will get back with you with his answer.

vetteguy75

I emailed him last night with your situation. At our local Chevy dealership, he is a GM World Class ASE Master Mechanic and is THE Corvette mechanic to go to, so I trust him completely with my Vette (He's been working on mine for the past 14 years). I recommend him to anyone with Corvette problems and I have never heard any complaints. Here is his response...hope it helps...

"I used voodoo to fix the light. just kidding. If he has not changed the light assembly to one like yours, he most likely has a short to ground on the door jam switch side, it's a white wire. Usually a bad door jam switch. Could be checked by removing switch and unplugging wire to open ground circuit.

Easy Mike

What model year? Later cars have a courtesy light delay after turning off the ignition and leaving the car.

my 76 ray

If the headlight switch is rotated all the way counter clockwise it keeps those lights on.

That circuit is always powered. The door switches provide a ground when the door is opened. That's how it works. If you have a short to ground the lights will stay on and as stated above the delay timer (if you have one) could be providing a ground for the circuit.

gbvette62

Mike, the OP said he has a 77.

77 was the first year that had a delay timer, in the courtesy light circuit.

The 77 timer was a one year only part, and completely different from the delay module that was used on 78-82 Corvettes. The timer is a small round metal can, sort of like a large capacitor. The GM part number is 461294. I think they were made by Phillips and have the Phillips name and part number on them, not the GM number. I think the 77 timer was mounted on the back of the right side dash panel.

The Corvette parts book actually lists the timer for 77 and 78 Corvettes. The 77 timer must have been used on early 78's, the ones that had the timer mounted near the steering column. Later 78's use the square orange plastic module, that's mounted to the right of the glove box, and above the dash vent.

Easy Mike

Sure did. I missed it.

gbvette62

There are enough posters who do leave the year they're working on, out of their posts. Let's not start picking on the ones, that do include it!

ezrider01

Hey all, thanks for all the enlightening discussion. After posting I did realize I forgot to mention that my application does NOT have the timer circuit.

I have also removed the door jam switch from the equation to negate a bad switch.

ezrider01

Could a bad headlight switch cause a short to ground therefore causing the dome & both curtesy lights????

I currently have a constant 12V at the light sockets....it's got to be a short to a ground somewhere....BUT WHERE?????

my 76 ray

Turn on the headlights and the dash lights should come on. By rotating the headlight switch clockwise you should be able to dim the dash lights. If they don't dim then your switch is definitely bad. If they do dim the switch could still be bad.

my 76 ray

Did you remove driver and passenger door jam switches? Also, I'm not sure about the '77's but my '76 and '74 have two door jamb switches on each door. The one at the rear of the door is for the alarm and the one at the front of the door controls the courtesy lights.

ezrider01

Hi. Thanks for your reply. No, I only removed / disconnected the driver side switch to see if i had a bad switch or something. I did not pull the pass side when I did this. Should I remove both?

Also, mine does have the alarm switches on the rear of the door jams but they are not connected.

ezrider01

So, yes, my headlight switch is correctly dimming my dash lights and yes my headlights do come on correctly as well. The only thing my headlight switch isn't controlling correctly are the curtesy / dome lights.

my 76 ray

Yes, I would remove both. They are connected by the white (I think) wire so if the passenger side is grounding the lights will stay on.

65GGvert

You should always have 12v on the door switches if you measure. When the door is opened, the door plunger switch grounds that voltage (it has already passed through the bulbs at this point). Only three things SHOULD provide a ground that will light up the lights. One and two are the door plunger switches. Three is rotating the headlight switch fully counter clockwise. All these things provide GROUND for the always present 12v on this circuit.
Remember, opening the door closes the switch providing ground and lighting the lights. Closing the door OPENS the switch removing ground. Any one of the three grounds will light both courtesy lights and the dome. The door could be not pressing the switch far enough to open it, but I think you said you tried by hand. Just disconnecting one door won't tell you much unless it happens to be the one providing the ground in question. Make sure the headlight switch is rotated away from the cc position and both door switches are OPEN (pressed in). If they are and you still have lights, you have a short on the ground side of one of the bulbs, either at the courtesy socket, or at the dome.

ezrider01

So to update...haven't made much progress so i decided to pull the lower dash panel and header panels to inspect the harness. While I'm in the open dash i am also replacing the main headlight switch just to rule that out. I have tested the door switches and verified those are functioning properly. I will post an update when i have it all put back together.

ezrider01

so my update to my update...with the opened driver side lower dash, I realized I DO HAVE the delay circuit....so I found one today on the Internet and have have it on order as well....so on this effort I have replaced the main switch, the delay timer, the delay timer harness, and verified the door switches. I have also checked the header harness that runs to the dome light...What else could I be missing????

ezrider01

So here is my close out report on this issue....
I replaced my courtesy delay timer switch & harness and main headlight switch (which turned out NOT to be the issue).

But I had a secondary issue in the circuit which I only figured out after I replaced a these switches...evidently the door jamb switch I was using on the passenger side was a bit short and not fully depressing the switch far enough to open the circuit for the lights to shut off...corrected that...confirmed the old delay switch was indeed bad also....and now problem solved.

THANK YOU to all of you who provided your valuable insight!!! This indeed is one awesome sight with a lot of nice folks wanting to help other out!!! Stay cool brothers & sisters!!!

drspencer

Would a '71 have the delay switch?

Thanks