Tow Dolly LED Brake Lights Blow Stop Light Fuse on RV But All Other Lights Work Fine

Question:

A used tow dolly with round LED lights just like the STL43RB blows the brake light fuse on my motorhome 2002 Fleetwood Discovery when the brakes are activated. The brake light fuse does not blow when the trailer harness is not hooked up. The turn signals and tail lights on the dolly work fine. It seems to me that since the turn signals work fine it cant be a short in the wiring they use the same wire or the fuse would blow on the turns too. Can the diode board or something else short out?

asked by: Steve H

Expert Reply:

There could be a short somewhere inside one of the lights causing the problem. There certainly is not enough power draw from LED lights to blow a stop light fuse on a vehicle so it would have to be a short somewhere. If everything works fine with a trailer connected and all of the other tow dolly lights work as they should then all signs point to an internal problem with the lights.

My recommendation is to replace the lights and inspect the wiring (just to be safe) and fix any broken or pinched wires. If # STL43RB is the same as what you have you can use it and the matching wiring harness is # A45PB. I do recommend using some dielectric grease, # LT37534, between electrical connections.

expert reply by: Michael H