I have a 2001 4dr Cavalier that has a back-up light problem. The back-up light on the drivers side works just fine, but the passenger side does not light up. Put in a new known good bulb in, and still did not work. With a test light, I checked for power. There was power to the green wire, and none to the black wire as I would expect. But when I put a bulb in, there is power at both green and black and the bulb is not lit. I replaced the socket with a new GM one, part number 89025036 but I had the same results. Swapped the working bulb from the drivers side to the passenger side and still get the same results. Anyone esle have this or have something else I should be checking?

Is there anything else not right with your car? Cuz my suggestion would be to check all fuses and relays, then start at the problem and back track that wire. Who knows. It could even be a grounding issue. I've seen some grounding issues that you'd shake your head at.

All the fuses check out ok. The only other problem is that the ABS light stays on most of the time. Occassionally it will go off for a period of a couple days, then come back on. Why the ABS codes are not part of the regular ODB-II diagnostic codes, I'll never know, except maybe to keep customers coming back to the dealership for checking out. I've seen one tester for about $300.00, but that is still too pricey for my toolbox.

You have a bad ground somewhere behind that connector in the chasis electrical system. If you getting power thats a good thing. You can do one of the following...

1)Ground that black wire somewhere to the car in the trunk, since the whole car is grounded it should work just fine.
2)Tear apart your whole rear dash and see where the wire is broke. Most likely somewhere in the wire loom that flexes when you open and close the trunk.