No Reverse Lights 95 Gr Cherokee

Perhaps someone can help me here. I have a 1995 Grand Cherokee, and I have no Reverse Lights. The auto parts store says thee is no sepereate revers light switch, its in the neutral safety switch, which i already replaced. I also replaced the bulbs, and lubricated the shift linkage. I had someone watch behind the car as I cycled through the gears and the lights didn't even flicker. I cant think of anything else that it could be. The only other thing is I nocied them out , the same day that I replace my alternator and battery. They may have been out prior to this, but im not sure, I just notcied it the same day. I cant see how that would have anything to do woth only the back up lights. Does anyone have any other ideas, I'd really appreciate the help. Thanks