Electrical problem
2003 Ford F150 V8 Four Wheel Drive Automatic 60000 miles
----------------------------------------------------------------
Truck park light fuse blows instantly with light switch on, ok in off position. Changed trailer plug,worked fine (all lights) for a few hours but back to square one now. Pulled trailer relay and fuse, no change. Tested and found continuity from both sides of fuse holder to ground (with fuse out). Any ideas where to find short that happened right out of the blue?