Chevrolet Repair: 1998 chevy truck, chevy 4x4, amp meter

Question
My 1998 chevy 4x4 k 1500 keeps blowing the park lamps fuse when i try to use running lights.I've checked it with a amp meter it only shows a draw 7.5 amps. they work fine for about 5 minutes all the wiring looks good trailer plug ok i checked all the bulbs and sockets.Any ideas

Answer
First will the fuse blow when you turn on the parking lamps without driving the vehicle? If no then movement or vibration in the circuit is causing the short.

I would remove all the bulbs on that circuit and road test the vehicle. If the fuse does not blow then it most likely is a shorted bulb. If the fuse blows then there is a short in the circuit that you'll have to trace down.

Trailer harness's have been a problem in the past. See if you can disconnect it and recheck the system.