MG Car Repair: 1980 MGB headlight problem, tracer wire, high beam

Question
Hi. The headlights work perfectly well, until the fill beam switch is put on the on position then the near side (driver)side goes out. The other one stays on. When the full beam is switch off, both headlights work fine. I have tried changing the headlight, the full beam switch and even the lights switch. All without luck. I assume it is a wiring problem, but the connection at both ends are tight.

Answer
Hi John,

There is only one wire going forward to operate the high beam and one for the low beam so when one light operates and the other don't it has to be a wiring problem between the two lights and that harness runs along the inside under the hood. The best way to find the problem is to turn on the high beam and test the wire at the operating light (where all the connectors are) and find the power with a 12v test light and then proceed across to the other side on the same color code wire. (blue w/white tracer wire)

Howard