I have a 1990 defender 90. RHD 200TDI. I put new RDX tail lights, signals, running lights and side signals in the front.
The issue I am having is that when I turn my left signal in it works until I turn on the head lights. When the headlights are on the right side is the only side that works. I checked the earth by the front which was fine. I took out of the cluster all of the earths that leads to the main and put the lights on the bottom of that cluster. Did not work.
I ran a earth line from the driver side that works to the passenger and still the same issue.

Anyone have anymore ideas than some of the gentlemen gave me already would help.