headligh switch problem

[trexse]

i have just picked up an 85 supra and noticed that when i turn the headlights on the parking lights come on but not the headlights. the lights pop-up but dont turn on. as i was checking over all the parts of the car i tried the horn and guess what? the headlights then turned on?? but no horn? could there be a problem in the switch or maybe in the steering column wiring? has anyone come across this? thanks

[Yenko]

Wow, thats one of the weirdest things ive ever heard of. Check wiring for sure. Do they turn on when you switch on the brights??

[trexse]

no they dont. the headlights wont work until i hit the horn? somtimes they will stay on once i jit the horn and i can drive but somtimes they shut right off? it weird i know:duh:

[84supra74vette]

Dude why fix that?

[trexse]

lol! well first it wont pass ny state inspection...the list goes on

[lechner]

Thinking this through, when you hit the horn button, you are providing a ground path for you horn through the horn button. Somehow, your headlights seem to also be grounding through the horn button. They probably stay on sometimes because they are pulling enough amps through that horn button to continue to jump the gap once they start to. If so, this is very dangerous because this wiring is not meant for this much power and could catch fire. I would NOT allow the headlights to stay on this way for any length of time.

I'm really not sure how your headlight ground wire has gotten crossed with your horn ground. Most likely, some half-assed wiring somebody added to the system at some point, perhaps add-on driving lights etc. Since your horn is near the headlights, I would carefully inspect the wiring in that area for signs of amateur wiring work and redo correctly anything that doesn't look factory.

[trexse]

thats what i was thinking. just wanted to know, if this was a known problem so i wouldnt be chasing this problem down for too long. thanks

[DeViaNt]

Yeah well, when i turn my lights on my radio goes off. How about that? lol

But the other night while I was coming home, the radio came back on mysteriously but the guage panel lights goes off and getting pulled over let me know that that also took my tails lights out. So now im effed for night driving until i figure it out =(

[lechner]

Deviant, your radio probably has circuitry that shuts it down if it isn't able to pull enough amps to work properly. Your alternator is probably not producing enough current to power everything. Perhaps you blew a fuse to your park lights, allowing that current to then power your radio? Either way you need to get your alternator tested.

[DeViaNt]

Well the thing with that is... when I got the car it had a factory deck in it that didnt play (but wasnt the original) and the wiring was all butchered. For some reason the light wiring was hooked to the radio wiring thanks to someone who had it in the past. Cause when I had my deck installed (sony) the lights didnt flip up at all. So with more wire tinkering it was all rigged together. I just dont understand why they were both together in the first place... and how the heck do i solve that?