Interior lights
Melting Slicks
Joined: Feb 2018
Posts: 2,327
Likes: 721
From: Marietta GA
PJC
i think you should first check positive voltage at the left side fuse box holder. If you don’t have voltage at that point, we will have to figure out where the voltage (wire) comes from. I know you previously mentioned checking the fuse box / fuse holder. Did you have one test lead on the left terminal and the other test lead to a known ground? You can use a volt meter or a test light, but you have to be touching some metal part under the dash to get a ground, along with the metal fuse holder, the headlight switch does not need to be pulled out.
Eli
i think you should first check positive voltage at the left side fuse box holder. If you don’t have voltage at that point, we will have to figure out where the voltage (wire) comes from. I know you previously mentioned checking the fuse box / fuse holder. Did you have one test lead on the left terminal and the other test lead to a known ground? You can use a volt meter or a test light, but you have to be touching some metal part under the dash to get a ground, along with the metal fuse holder, the headlight switch does not need to be pulled out.
Eli
Race Director
Joined: Mar 2017
Posts: 11,953
Likes: 4,508
From: Virginia
What @Eliredandblack suggested is a much easier first check. I find it helpful to take the seat out when working under the dash. Some folks line up platforms to lay flat at an angle.
Anyway, I meant to test the leads as best you can before removing the new switch. I don't know if you can in a 72. There may be more room in an 80, so I dont mean to suggest something imppssible.
Anyway, I meant to test the leads as best you can before removing the new switch. I don't know if you can in a 72. There may be more room in an 80, so I dont mean to suggest something imppssible.
Drifting
Joined: Nov 2019
Posts: 1,369
Likes: 99
bikespace
I installed a new headlight switch last month. everything works (headlights, parking lights and courtesy lights) but not the interior lights (speed-0, rpm, all the gauges).
I will try all that you suggested with respect to new fuse and clean contacts.
thank you for the schematics. I will print them out.
I do have a question. My car is a '72. is there any info that tells me where and what the grounds are look like (pictures/drawings) for the dash and gauges?
I've sent Papawana an email last Sat.
thx
pjc
I installed a new headlight switch last month. everything works (headlights, parking lights and courtesy lights) but not the interior lights (speed-0, rpm, all the gauges).
I will try all that you suggested with respect to new fuse and clean contacts.
thank you for the schematics. I will print them out.
I do have a question. My car is a '72. is there any info that tells me where and what the grounds are look like (pictures/drawings) for the dash and gauges?
I've sent Papawana an email last Sat.
thx
pjc
Intermediate
Joined: Nov 2017
Posts: 37
Likes: 2
The round black plastic bezel has a broken piece that holds the headlight switch to the dash panel. In order to see the problem, you need to remove the push/pull **** from the headlight switch. there is an excellent YouTube video the shows you how you can fix it.
Melting Slicks
Joined: Feb 2018
Posts: 2,327
Likes: 721
From: Marietta GA
pJC
With all my long winded posts, you may have missed a comment about a piece of metal/arm on the back of the headlight switch that touches the metal back of the speedo housing. This piece of metal is the Ground for the headlight switch, I noticed that Elcran mentioned that his bezel was broken, and the metal being loose could cause your problem. If you don’t want to tear into the dash, a bore scope camera may come in handy. HD has them and you can use it for other problems down the road.
With all my long winded posts, you may have missed a comment about a piece of metal/arm on the back of the headlight switch that touches the metal back of the speedo housing. This piece of metal is the Ground for the headlight switch, I noticed that Elcran mentioned that his bezel was broken, and the metal being loose could cause your problem. If you don’t want to tear into the dash, a bore scope camera may come in handy. HD has them and you can use it for other problems down the road.
Melting Slicks
Joined: Feb 2018
Posts: 2,327
Likes: 721
From: Marietta GA
I never tried from below, since my car is a convertible there is a brace under the drivers side dash. You can remove the door threshold, then the plastic kick panel. Next remove the screws on the drivers dash pad, also the bottom plastic piece under the steering column. Remove the two screws on the inside of the center gauge cluster. I also may have remove the screw holding the trip reset/vac override. After doing all the above, you should be able to pull the dad out enough to push the button to release the headlight ****. I assume you have, or made the tool to unscrew the special nut that holds the bezel/switch in the dash. Make sure you have the metal arm Ground orientated so it touches the speedo metal housing.
Intermediate
Joined: Nov 2017
Posts: 37
Likes: 2
Eli, Here's the latest episode on the interior lights. I checked the ground strap that goes around the headlight sw. and it's in place.
This morning I tried another approach. I ran a jumper from the batt + to the left side of the fuse holder (with new fuse). Measured 12 volts applied at the fuse with a voltmeter. I turned on the ignition sw. and pulled the headlight sw, to the parking lights position. Turned the potentiometer from low to high. No interior lights came on.
Next, I added another jumper from the Dk. green (should be the hot) wire in the headlight sw, connector to the jumper at the fuse panel (my thinking was to get 12 volts up to the headlight sw). I turned on the ignition sw and pulled the headlight sw. to the parking light position. I turned the potentiometer from high to low. No interior lights came on. However, the left directional light came on and went from low to high as I turned the pot. The directional light lever was in the neutral position I also heard a clicking sound from under the dash. similar to a relay cycling. Don't know what any of this means.
My car was owned by numerous people and the wiring under dash has been changed over the years. Not a nice problem to solve.
To all my forum friends who have tried to help me, a big thank you!!
pjc
This morning I tried another approach. I ran a jumper from the batt + to the left side of the fuse holder (with new fuse). Measured 12 volts applied at the fuse with a voltmeter. I turned on the ignition sw. and pulled the headlight sw, to the parking lights position. Turned the potentiometer from low to high. No interior lights came on.
Next, I added another jumper from the Dk. green (should be the hot) wire in the headlight sw, connector to the jumper at the fuse panel (my thinking was to get 12 volts up to the headlight sw). I turned on the ignition sw and pulled the headlight sw. to the parking light position. I turned the potentiometer from high to low. No interior lights came on. However, the left directional light came on and went from low to high as I turned the pot. The directional light lever was in the neutral position I also heard a clicking sound from under the dash. similar to a relay cycling. Don't know what any of this means.
My car was owned by numerous people and the wiring under dash has been changed over the years. Not a nice problem to solve.
To all my forum friends who have tried to help me, a big thank you!!
pjc
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