My tail lights and instrument panel lights havent worked for about 2 weeks now and i cant seem to figure out the problem.(lights do come on when brakes are applied) It is blowing a fuse every time i turn the headlights on and ive checked the tail light relay, wiring from passenger side of cab back to lights and there are no shorts. i cant seem to find what is causing it to blow fuses. Any ideas? Is this a common problem? the only thing i can think of is i may have nicked a wire when installing my radio, but the wires looked fine when i inspected them.

 

Try disconnecting the radio and re-test. I had similar issues when I first installed a radio in my '85 trying to make use of the PO's hacked up wiring. I eventually abandoned all the original wires (except to the speakers) and ran my own power and ground wires and no more lighting issues. Often the cause is the radio back light wire.

 

I had the same problem with my 86. Check the plug underneath the passenger seat under the carpet mine came unplugged and my cluster and tail lights wouldn't work. Plugged it back in and bam. Just a thought.