Hey guys!

I have an interesting one for you.

The parking lights (gauge lights, side lights, tail lights and front turn signals) won't turn off. I pushed the headlight switch in all the way and still nothing.

Checked all the wires underneath and couldn't find anything unusual...checked fuses for everything and it all looked good. Can't be the trailer wiring because it's all disconnected as of right now.

Anyone have any ideas? I'm leaning to thinking it's a bad headlight switch.

 

The headlight switch would be my first thought, too; the exterior lamps are fed by a solid-brown wire, the dash gauges by a light blue/red-tracer wire.

There is a certain wire that's well-known for overheating & melting itself + adjacent wires near the headlamp switch, I think it's tan in color. Be sure to look at that + all those wires closely while you have it disassembled to make sure nothing has been damaged and shorted.

 

The lights are getting power from somewhere. The first thing to do is pull the fuses one at a time and see if the lights go out. If they do, that is the problem circuit. It can be something simple like someone hooking up a wrong wire during a stereo install and causing this. If they accidentally hook power all the time to the blue/red wire, that is the instrument cluster illumination wire and the power would backfeed through the illumination fuse to the headlight switch where it would power the brown running light circuit.

 

Thank you! I will have to look into that.

I tried this when it first happened and the only fuses that shut it off was fuse 4 & fuse 17 killed the dash lights as it should.

I installed the radio myself and used an adapter harness that plugged into the factory plug - so it's all factory wiring. The radio has been installed for weeks now and never given issue.

Before this issue I was replacing my mechanical temp gauge and even though I drained a **** ton of coolant out of the radiator when I pulled the temp sender it was like a fountain for a second and coolant got ALL over the fender where some of the wiring is. I quickly pulled it up so coolant didn't get on it, but still I'm not sure if that played a part at all. I checked all the connections and wires very closely afterwards, but I don't think that it had any affect other than maybe killing the headlight switch?

 

I corrected my post, the famous melting wire is near the headlamp switch, not turn signal switch as I had said earlier.

 

If fuse #4 turned them off, I agree there is something wrong with the headlight switch, or the wiring is burnt or melted near the headlight switch. Being they went out when you pulled #4, that is telling us that this circuit is not being backfed from any other hot wire in the truck. So what normally turns them on and off is not working.

 

Replaced the headlight switch last night and it fixed it.