My fuse keeps blowing on my reverse lights. It doesnt always blow immediately, but usually after a few back ups. fuse is 20amps

Any tips on how to track this down easily?

 

check the switch and wires on trans maybe 1 is cut or shorting out some how then trace them as they go back on frame rail .

 

Check your 7-way trailer connector if you have one, mud, slush and road salts will short circuits to ground or to each other, also check for pinched or abraded wires in the harness along the frame.
Jim

 

I don't know this wiring, but can't you remove the fuse then check hot wires to lights for continuity to ground, to at least show which side is the shorting problem?

 

Sometimes the harness gets trapped between the spare tire and the frame. Shorts happen. Like Jim says they happen most often in the trailer connector. I just bought an assortment of solder lugs with varying wire sizes and #6 holes. Next time I have to go into mine I'm going to wire it so it doesn't get rearranged every time I hit a snow bank or something.

 

Immediately behind the taillight assy seems to be a common place for the harness to get pinched and short out
IIRC the lighting harness runs down the driver aside frame rail and across to the passenger side..tho I'm not 100% sure of that