Headlight problem 1992 Corvette
Thread Starter
Navigator
Joined: Sep 2019
Posts: 9
Likes: 0
From: Northville, NY
Headlight problem 1992 Corvette
My headlights work fine as long as fog lights are off. If I turn on the fog lights, the headlights automatically go onto high beam and will not dim down to low beam. Any ideas what the problem is would be great.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 207
From: Orlando FL
Such a strange problem. In reviewing the circuits for my 94, they are probably very close. This is definitely a strange circuit as how the design is for the dimmer switch and fog relay.
There is a diode in the headlight switch that feeds the fog light relay. The other end of the relay coil goes back to the high beam headlight. If the diode shorted it might me doing something strange like supplying power to the high beam headlight. As you change to low beam you might not be able to "see" the difference in light. (Possibly bad headlight switch).
You say the hi-low headlight switch is basically working so that sounds OK
The fog lights work so it seems the fog light relay is working.
The difference in the 92 vs. the 94 is the ECM and PCM. It is part of the hi-beam indicator control. Don’t know if that could be a factor or not, but not really related to fog lights.
This is all opinion based on my book. I can't really nail down the problem without making my own measurements so it's the best I can do for now, take it with a grain of salt
There is a diode in the headlight switch that feeds the fog light relay. The other end of the relay coil goes back to the high beam headlight. If the diode shorted it might me doing something strange like supplying power to the high beam headlight. As you change to low beam you might not be able to "see" the difference in light. (Possibly bad headlight switch).
You say the hi-low headlight switch is basically working so that sounds OK
The fog lights work so it seems the fog light relay is working.
The difference in the 92 vs. the 94 is the ECM and PCM. It is part of the hi-beam indicator control. Don’t know if that could be a factor or not, but not really related to fog lights.
This is all opinion based on my book. I can't really nail down the problem without making my own measurements so it's the best I can do for now, take it with a grain of salt
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 207
From: Orlando FL
Hard to say where to exactly look for it.
Have you had any part of the car apart or done work on it before the problem occurred?
Thread Starter
Navigator
Joined: Sep 2019
Posts: 9
Likes: 0
From: Northville, NY
No. Have had this problem since I got the car earlier this year. Talk to the guy I bought it from and he said he never had a problem with the lights.
