2005 regular cab bought used reverse lights didn't work. Tried to fix it by changing the reverse switch worked for a few days gave out. Tested the wiring from the switch didn't blow the fuse wiring should be ok. Changed the reverse lights are ok. Changed the rear lights to l.e.d. did the same thing. What am I missing that's causing the fuse to blow. 15 amp fuse reverse. I need to have this fixed for safety reasons. Please help.