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I've got an 85 with the headlight module set up. I've been told that these should have had the three relays, but mine has the module. Apparently some 85s had these.
My driver side light will flip up but my passenger light does not. The lamps will turn on, but only one motor spins. I've jumped 12v to both headlights and they both will flip up. Doing some research/testing has me believing the module I have has gone bad. These buggers are expensive to replace. Is there ANYTHING, I can do to by-pass this module to get my headlights to work (such as, rewiring to traditional relays)? Has anyone on here experienced this issue? What was your fix? Can this be done?
I have a 1997 Firebird that has a head light module. I took it out and put in in the vette and the lights did not turn on or flip. So I'm assuming by 1997 the GM headlight module has been updated? I'm seeing C5 modules that have 1997-2004 model years and I'm seeing C4 modules that state 1984-1996 model year range. So maybe that's why my 97 bird module didn't work on my 85 vette.
I'd like to figure this out safely and for as little of a punch to my wallet as possible.
I just dealt with issues with my headlights but I have a 89. If you call Mark at Mirrock and talk to him he is very knowledgable about the C4. I was very pleased with his help and replacement part I got from him. Module for me was $97.50
Your 85 would have come with the three relay setup. Some of the catalog companies a way back sold an update to go to the headlight module in the earlier cars.
It sounds like you have done the correct troubleshooting and have isolated it to the module. I would stress buying a good used one one over one of the cheap quality reproductions.
Your 85 would have come with the three relay setup. Some of the catalog companies a way back sold an update to go to the headlight module in the earlier cars.
It sounds like you have done the correct troubleshooting and have isolated it to the module. I would stress buying a good used one one over one of the cheap quality reproductions.
Is there an advantage to having the "module" over the three relays? Can I revert back? Relays are so much cheaper to replace than this computer board.
Judging by your user name you might like the way I repaired the same issue in my 84. At some point the previous owner had hacked in two wire headlight motors instead of the three wire versions that were supposed to be there. This conversion wasn't done very well and it led to a bad drain on the battery. That and the lights would just work when they wanted to. So I put in a small rocker switch and a relay box that I got off ebay.
So I removed all the factory relays and threw them away. Then I started from scratch. So the toggle switch raises and lowers the light buckets just like power windows. The factory pull switch turns the bulbs on and off. In the last picture you can see how I have it labeled. One 5 pin relay for lights up and another for down. One 4 pin for bulbs on low and another for high beam. Then the brown one is a 4 pin I used for the fog lights. The whole thing cost about $40 and it works every time.
Judging by your user name you might like the way I repaired the same issue in my 84. At some point the previous owner had hacked in two wire headlight motors instead of the three wire versions that were supposed to be there. This conversion wasn't done very well and it led to a bad drain on the battery. That and the lights would just work when they wanted to. So I put in a small rocker switch and a relay box that I got off ebay.
So I removed all the factory relays and threw them away. Then I started from scratch. So the toggle switch raises and lowers the light buckets just like power windows. The factory pull switch turns the bulbs on and off. In the last picture you can see how I have it labeled. One 5 pin relay for lights up and another for down. One 4 pin for bulbs on low and another for high beam. Then the brown one is a 4 pin I used for the fog lights. The whole thing cost about $40 and it works every time.
My '85 has the two wire headlight bucket motors. I'm electrical systems illiterate. I'm currently trying to source a new module, but in the mean time I'm interested in learning as much as I can about a retrofit or alteration to make these things work right.
Headlight Module - help!
