I purchased a new trailer wire harness directly from Atlantic British last year and installed it myself. My trailer lights worked perfectly (running, brake, turns and hazards). After 3 months, my running lights stopped working. I still had Brake, Turn and Hazards, but no running lights. I tested the trailer on two other vehicles with the same connect setup (4 in-line prongs). I thought there might be a defect in the harness so I did an even exchange for a brand new one. Installed the new harness and the same thing happened...No running lights but all other lights work. I checked #14 fuse and its good. All lights on the RR Sport work fine, including the regular running lights. BTW, I'm using reg 12v lights, not LED. When I called Atlantic British back, they said I needed to take it to the LR dealership to have the mod reset?? Not sure what they mean by that and not sure what would cause this to even happen, since it all worked fine at the first install. Any advise would be much appreciated. Thanks

 

I would call a local LR dealer and see which is less expensive O.E. harness or diagnostics