My son's 2000 f 150 Dash lights are out fuse keeps blowing. Changed the light switch. still blows. unplugged harnesses installed new fuse plugged in headlight harness ok plugged in, I guess dimmer harness fuse blows but the dimmer switch still controls cabin light? The first time I changed the fuse it stayed lit for a min. or 2, now it just blow immediately. Anybody got some fixes?