There is a connector on top of tranny on passemger side with 2 wires that go to your reverse switch. In that area you will probably be able to find your problem. First put it in reverse and check for continuity at the switch poles. if you have continuity then I'd start checking the conector and trace the wires back to lights looking for breaks in the wire. If you don't have continuity at the switch then I'd suspect the switch. Good luck and hope this helps.