Bonej

I am having a problem with my lights. I keep burning out light switches and the harness. The red wire that goes into the light switch harness which is the constant power keeps heating up and melting the harness and switch. The switch works in postion one the parking lights come on but in 2 everything goes off. I am not blowing any fuses so it is after the fuse box i think. I took apart the wiring and traced the red wire to see if it is touching any metal but it isnt. also when i hold the highs on with the light switch is postion 2 it acts like i have the ignition on acc everything works( windows. wipers, etc.) I think it is either a bad ground or a relay. I was thinking maybe the load reduction realy might be bad because when i unplug the relay it doesnt do the high beam thing. But i really dont know what the purpose of that relay is. all i know that in the bentley manual i looks like the ignition and the light switch is tied to that relay. Please help i need to drive my car at night again. Also i cant seem to find any bad grounds so any hints where to look would help or basically any info

Thanks
87 4000csq without lights

cello

I don't recall if the lows are relayed. But, I do know that ALOT of current goes through that switch. I mean, it gets HOT. I've melted these switches in the past, just replacing them from ones in salvages yards (when I find ones that aren't melted), so my guess would be the switch itself. Parking lights work, lows don't and everything goes out.

Ever since replacing them with Euros and throwing relays on both highs and lows, I haven't had a problem at all. The switch doesn't get hot anymore either.

Just my experience,
Cello

eharleq

Same solution. Just relay them off.

SurfinSilly

Will relaying the low beam make the headlight sensor go off on the computer inside?

cello

It shouldn't, as long as both sides have equal voltage. But, I don't think his car has has the headlight sensor anyway. Mine doesn't.

eharleq

My 86 doesn't have a sensor that I could tell. No problems after 40k.