'86 IROC TPI
My headlights will turn on fine. Put my brights on, works fine. Go to dim them, don't work, they stay on bright, but the dash indicator goes off. The only way to turn the brights off is to turn the lights off completely. Yes, all the lights stay on even when in park. But the lights shut off fine if just the dims are on.
I have put the headlight wiring mod on that is described elsewhere here as the headlights didnt work worth a darm before that (had 1 dim dim that would work). The relays are triggerred off of one of the original headlight connectors... could it be that the switch isnt getting enough of a current draw to work as in what messes up the parking lights when one goes out?

 

I was studying the wiring diagram and something that was puzzling me earlier about it is starting to make some sense now, and could be the cause of my problem, but I havent had the time yet to actually check it out on the car.
The fog lamp relay is powered off of the park/head setting, and then goes to the high beam wiring, so that when you put the high beams on, the relay is effectively turned off.
The way to check this would be to disconnect the relay and see if the headlights work correctly. If this is the problem, I will have to decide to either totally remove the fog lights, or to rewire the relay to work in a different way.
So now the question is: Where is the fog light relay physically located?
TIA
James
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yes, that is the problem, now to just fix it. right now I have it temporarily 'fixed' by disconnecting the fog light relay... just means I dont have fog lights right now.

 

Did you ever get your issue fixed with the lights? I have the exact same issue.

Yes I know this is an old post but it came up in a search.

 

OMG
I haven't had the IROC in 20 years. It got totalled in an accident when a young girl made a left turn into my path when I was doing about 50. After that, I had an '89 GTA that I then got rid of in either '04 or '05, and have been through a few different cars/trucks since then.
If I remember right, these cars had some weird wiring on the low beam side where they were essentially wired in series for DRL and then it went into parallel for regular lights. My issue had something to do with that relay I mentioned above, but honestly I don't really remember what I did if anything. It wasn't too long after this that it got totalled, then I had the issues with the GTA
If you have something like a Chiltons or Haynes manual, just follow the wiring diagram and you may be able to figure out what I am talking about here. If you still can't get it, give me a holler back and I will see if I can find something.
James

 

I appreciate your reply. I figured out that when I removed the relay my headlights function as they are supposed to. Previous owner cut the factory plugs off for the driving lights and removed factory switch. I just replaced the pigtails and installed the factory switch and found my issues. I did do the wiring harness upgrade for the lights and followed the upgrade diagram and first ran into dimming issues. I'll keep digging and see what I come up with. Thanks again.