For the last couple of years the passenger side rear running light on my '93 GTS never illuminated when the driving lights were turned on. It really bugged me - getting the warning light whenever I turned on the driving lights and not having the illumination on the passenger side.

After all manner of trouble shooting - bulb check, re-cleaning grounds, relay testing - I finally found the culprit. The front passenger side H3 driving light! Although the light functioned - the connector from the light to the wiring harness had a corroded to a point where there was not sufficient ground contact to complete the circuit for the rear driving light.

Yesterday, after replacing the bulb the rear driving light now works!!

 

That sounds like it would have been a pain in the *** to figure out. Well done.

 

indeed, good work. i hate it when something WAY ON THE OTHER SIDE of the car , is causing the problem far far away...