I would have to agree with f350xlt460, if the fuses are blowing there is a reason. I think tracing a short out would be far easier than trying to repair a burnt down rig. If you have a volt meter, start at the plug in the back. Ohm each wire to ground, ground should read Zero Ohms, the rest should read open. Then check between each wire. It a place to start, and you need to start somewhere. Also, drop the spare tire, there should be on the driver side frame rail a large interconnect for all the tail lights and Trailer wiring. Make sure you are getting good contacts there. You may want to check your trailer wires there for voltage. Good luck at any rate, going to take some time to figure it out.

Mike