I have a teardrop trailer which I tow with my Mini Cooper S. I have 2 wiring harnesses to the trailer: 4 wire for running lights, brake lights and turn signals and a 2 wire to charge a set of 12v agm batteries. The 4 wire is not working correctly. The running lights, brake lights and the left turn signal work but the right turn signal does not. What can I do?
Check the bulb's first. Get yourself a test light, using a process of elimination locate the wire that feeds the non-functioning turn signal. Turn on the turn signal, using your test light trace the wire checking for voltage as you trace it back to its origination point.
If you find no defects in the wire then check the turn signal mechanism inside the steering column.