I have a 92 U42T Minicab, sweet truck no issues other than it keeps popping the Parking Light Fuse which also controls the lights in the dash cluster and possibly the brake lights. I've done nothing to the truck other than lift it 8 inches and install a aftermarket stereo and speakers. I've installed a ton of radios in my life time and don't feel I did anything to cause this, I used the factory radio wires for the constant power and the key on power and ran my own speaker wires to the doors, radio works fine as does everything else. Anyone have any ideas?? I even popped a 30amp fuse in the spot to see if it would hold and it pops instantly as well, something somewhere is directly shorted. Thanks
Sounds like you either pinched a wire somewhere when doing the lift or shorted doing the radio install. Use a test light instead of a fuse across the 2 fuse terminals and it will stay lit as long as you have the short. Then you can go about searching for the short itself. The light will go out when you eliminate the short. You can also use a door buzzer in place of the fuse, then you only have to listen for the buzz while searching. Fred
I dont see anything pinched from the lift and all worked after the lift, I'll have to double check the radio install but it was all good after that too. Seems something just went to crap somewhere.
In the past I have found that sometime after a radio or other equipment install a mounting screw had rubbed through the insulation as it was tight up against the wire and eventually wore through. It sure sounds as if you have a direct short, best find & repair before it decides to let all the smoke out, cause then you will have to do some rewiring. Could also be coincidential that one of the light sockets could have decided to short out at this time. Fred
I've traced everything I can with no luck, I've unplugged each light ect one at a time while using the light bulb in the fuse socket trick with no luck. The bulb lights up when the light switch is on or when you press the brake pedal. Very frustrating. I have even removed the radio completely to eliminate that as a possibility, the one this I did notice when messing with the radio is that when the metal from the radio touches the metal of the truck the bulb would get a bit brighter. I've traced the harnesses and wiggled them ect and nothing.
Did you figure out the problem? I found another post on here with the same issue and his problem was using the ground wire in the stereo loom. For some reason, that caused the tail light and dash light fuse to blow when the headlights turn on. I have the same issue after installing the radio. I'll be moving the ground wire to a permanent ground and I'll report back.
This thread is 6 years since last update and the OP was last on here in 2017. The issue with many of these trucks is the ground is switched to a hot wire when the lights are turned on. So the radio works using the ground all day until you turn on some lights, the boom the fuse blows. I direct wired the a switched + in an unused slot in the fuse block and the - I wired to the radio chassis.