I have a 1986 firebird and have had some issues with the headlight and have heard a common issue is down to the headlight module, so I tried looking for it in my car but can't find it anywhere. Does is even exist on the 1986 models?

 

Bump, I have an 86 too and have narrowed my problems down to the module but it seems that they are only available for 87-92

 

Wow, this thread is a bit of a blast from the past Can you describe your issue? I may be able to help you out with it.

 

Thanks for the help, I just put a new battery and alternator in, the voltage was a steady 14 and everything seemed good, my headlights always flickered but just last night they would shut off and come back on and flicker while driving, the volts also dropped to 12.5 with the motor running, the flickering had no affect on voltage. I started the car this morning and now the headlights won't pop up but I do believe they're on, I'm pretty sure it's either a problem with the fusible link between the alternator and battery or one of the three relays for the headlights, would the relays cause a voltage drop?

 

Very weird, that's the exact same issue that happened to my old 86 the last night I had it. The lights came on but wouldn't pop up, had to rely on my ambers to make it home. In theory, a relay is the same as a piece of wire when it is closed (or "on"), and, just like wire, are not considered a significant enough source of resistance to be accounted for, except in the case of very high wattage or very sensitive systems. In actual truth, yes, they have resistance... but it's so small that it's (usually) irrelevant. So if your relay was bad, it wouldn't gradually degrade in voltage to a significant level. Have you checked your grounds or any breaks in the wire throughout the headlight harness?

 

That's what I was thinking, when I got the car it had a disconnected body ground from the negative battery terminal to the radiator support, I reconnected it but I don't think it's making a good enough connection, I'm gonna grind it down to bare metal and re connect when I get home and replace the dimmer switch. I just don't get why I had perfect voltage and then this randomly happened. Also the previous owner taped up the fusible link and when I took off the tape it was highly corroded with exposed wire, do you know of any way to replace or get rid of this fuse properly? Thanks for your input