Cleaned the earths by both headlamps and the fault is still there If I check the voltage on the brown wire and yellow wire on the back of the bulb I get 6 volts on the passenger headlight and 5 volts on the drivers one. This is with the switch in either side or dipped beam position. If I check the voltage at the plug that plugs into the lights I get 13 volts (with engine running) at the passenger side and nothing on the drivers side.

What does that suggest please?

Thanks