Interior Light Demon
Thread Starter
Intermediate
Joined: Oct 2013
Posts: 36
Likes: 1
Interior Light Demon
When I had my dash half way installed every light and switch in my 1968 convertible restoration project was working. Now that I have the dash, center console and rear compartment light installed my interior lights stay on when the doors are closed. I pulled out left and right front door jamb switches to check the wires and the lights are still on. I am looking at the wiring diagram to try to figure out where I could be picking up a ground that I am not supposed to but I am not sure I can figure out where to start isolating the circuit. Does anyone have an idea where I could have gone wrong or where I should look to isolate the ground circuit? Is there another switch in the circuit that I have missed? I also have a new head light switch that seemed to be operating the interior lights correctly originally. Thanks for the help.
Thread Starter
Intermediate
Joined: Oct 2013
Posts: 36
Likes: 1
Thanks for the reply. I was hoping I had missed something. The switch originally worked correctly. As you could assume I was hoping not to pull the dash again. Oh well. Chalk it up to yet another C3 challenge.
Team Owner
Joined: Jul 2006
Posts: 22,190
Likes: 4,178
From: Kannapolis NC
The dash and center console lights are grounded all the time. Turning on the park or headlights switches 12v to them. The rear compartment light always has 12v and opening the door or rotating the headlamp switch grounds it along with the courtesy lights. The dash lights are not on that ground circuit with the courtesy and rear compartment lights. Either something is wired wrong feeding voltage where it shouldn't, or you have more than one issue. Are the courtesy lights coming on and off with the door opening.
Thread Starter
Intermediate
Joined: Oct 2013
Posts: 36
Likes: 1
The courtesy lights are always on when the battery is hooked up. Maybe I am picking up 12v somewhere when I finished installing the dash, gauge cluster and center console. No other dash lights are backing feeding which I assume might happen if that were the case. All other lights and gauges seem to be operating correctly.
Racer
Joined: Nov 2014
Posts: 463
Likes: 129
The courtesy lights are on there own circuit separate from the other dash lights. The only common link they have is the head light switch. I'd start there. Is the new switch a repro or a real NOS GM? I wouldn't trust a repro headlight switch on my car.
If the door jam switches are pulled from the body the courtesy lights shouldn't work.
Also try pulling the courtesy light fuse. Do the lights still work?
John
Thread Starter
Intermediate
Joined: Oct 2013
Posts: 36
Likes: 1
I think it is a repo switch.
The position of the switch does not matter even with the door switches pulled.
I think I will try the fuse first to make sure the problem is limited to that circuit. From there I will have to pull the light switch. I still have the original. I replaced it just for good measures while everything was tore apart.
Thanks
The position of the switch does not matter even with the door switches pulled.
I think I will try the fuse first to make sure the problem is limited to that circuit. From there I will have to pull the light switch. I still have the original. I replaced it just for good measures while everything was tore apart.
Thanks
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Team Owner
Joined: Jul 2006
Posts: 22,190
Likes: 4,178
From: Kannapolis NC
You've got two different issues. They may have a common cause, but the dash lights don't come on with a change of ground. They are always grounded and 12v is applied through the switch. The courtesy lights are the opposite. They always have 12v and turning the switch or opening the doors applies a ground. Unless (and this is wild conjecture) you have the two connected and the 12v is feeding from the courtesy light circuit to the dash lamps, and that provides a ground for the courtesy lights through the dash lights. Check to see if you can find any place the courtesy light wire is connected to the dash lamp wires.
Thread Starter
Intermediate
Joined: Oct 2013
Posts: 36
Likes: 1
I pulled the fuse quick and the lights go out. Because they worked at one time my bet is something in the switch but it will take a little to time to get at it. If I unplug the switch the lights should go out. If they don't then it will get real interesting. I will let you know how it comes out.
Thread Starter
Intermediate
Joined: Oct 2013
Posts: 36
Likes: 1
A quick update. After thinking about it for a couple of days I decided today was the day to take the dash apart to find the light problem. Fortunately the fix was easy. I had the dash lose and was starting to pull it out when the light started to flicker. I crawled underneath again and found that the drivers side bulb must have popped out when I was installing the tube to the drivers side vent. I looked to be still in place but pulled out just far enough to short the base of the bulb to the metal bracket. I popped it back into the hole and all is good. It shows once again that it is the simplest things that can bite you in the back side. Thanks for everyone's input.
