I'm having serious issues with my chevy truck. It keeps blowing fuses in the running lights. It's a 2000 dually 4X4. I've taken all the trailer wiring apart and checked all connections, replaced the light switch. The lights woyld stay on for an hour or so, then blow. Now, it pops as soon as the fuse is replaced.

I would look inside all of the sockets, I had a small trailer do the same thing and found a socket corroded and the base of the light making a short.

I'm in that process right now. I have every light out. They're all burning. Last night, we had the lights on and they seemed to be working. The fuse blew and after that, the fuse would blow instantly. This morning the lights are working.

This may or may not help narrow down the possibilities, but I have seen some problems with the dome light circuits on Chevy trucks, and, I seem to remember a TSB on it...there is a place in the wiring that will short out against the cab, and blow the fuse. Most of the ones I've seen have been either at the base of the "B" pillar(door latch), or across the roof of the cab. I believe the TSB was put out concerning chaffing of the harness around the dome light bezel.

I'll look and see can I dig that up...

 Field mice love wire insulation. hope it's what joel suggested

I think I found the culprit! Looks like a small nick on a front parking light wire. I see a little black on the cowl behind it and as soon as I tightened up the lens, "POP!" hAVE TO GO GET MY GLASSES TO REALLY BE SURE THAT THE WIRE IS NICKED????????

We'll keep our fangers crossed, Dave!!! Hope that's the fix...

So far, the lights are staying on! I've been cycling them off and on for a while. I'm pretty sure now the nick was the culprit. I did find a bad bulb and though that was it. When I took it out to check the socket, the globe came out, but the base stayed in the hole. filament was still good and the light would burn, but the socket was full of corrosion. Not sure why it was even working?

Be sure to put a little bit of dielectric grease in the socket to prevent the bulb from having problems again.

Sounds like a neat trick Ken! I'll keep it in mind if I have another issue like this. So far everything is working, I'm working on a project in Ga. right now and left N.C. this morning. I'm leaving here to go to fla wednesday after work. The lamps in the truck were pretty gooped up to start with, so i left most of the grease in them. I'm pretty sure the small nick in the wire I found was a gift from the factory. I bought the truck new and have never had to mess with any of the lights.