taillights are out/blowing fuses

The tail lights on my 85 s10 are out. The headlights work and the brake lights work. Each time I replace the fuse and turn the lights on the fuse blows. I have replaced the light switch and still continue to blow the fuse. I do not know where to look next.

You didn't happen to just put in a new radio did you? Is there a trailer light adapter on it? Those are two things I'd look at. I'd also get underneath the box and check out the harness that goes to the rear, if you find a coupling near the rear bumper, disconnect it and see if it blows another fuse, if it doesn't you've narrowed your search for a short

No, I did not put in a new radio but about the same day the lights went out the radio quit. Then going down the road it came back on. I didn.t make a connection until now. I'll start there. Anymore suggestions?

If it is still a factory radio its probably a dead end, but if its aftermarket, some wiring may be coming apart

Jeremy,
Thanks for the suggestions. I was out of ideas. I'll try pulling the radio and see if I have any luck.

check the rear lights look for broun wire this is your tail light wire make sure is not grounded
then check the front light
check the rear wiring harness under carpet the driver side

climb under the truck and follow the wires on the way back make sure none of them have any sheathing pulled back or any wire is exposed, also check all your grounds make sure none are off or coming loose