My buddy has a 1990 Cadillac Fleetwood and his running light/license plate light/instrument cluster fuse (fuse #14, 20 amp) keeps blowing?? If you try to put a fuse in with the battery connected it sparks and will shock you. Any suggestions on to why it keeps blowing and is shorting? Would a blown bulb cause it to do that? Would the wrong harness for the head unit have any thing to do with it?