no dash lights or park lights

[bostterr1]

anyone have a clue why i keep blowing the park lights fuse every time i turn the headlight switch on, i have no park lights and no dash lights, i thought i found the problem with a bad ground at the rear taillight harness, put a new fuse in and everything worked, later in the day the fuse blew and lights went out again, only my headlights and brake lights work, then i took the switch apart and cleaned it up and still nothing, BTW its a 1999 gmc 2500 6.5 Turbo

[trbankii]

Obviously shorting out somewhere. The fact that working on the ground at the taillight helped for awhile seems to sound like you were in the right vicinity of the problem. I'd take things apart there again and check out the wires closely. Perhaps there is a bare wire somewhere and when you worked on it before you moved the wire away from any contact - when it moved back (from being jostled while driving) it shorted out again.

I had a similar problem on my Toyota truck. I'd blow the fuse whenever it rained. Turned out to be an abraded wire and when things got wet it would short out. A bit of electrical tape and I was back in business.