I had an issue on my 01 ram. The pin style connectors they use for the reverse light switch wasn't making good contact. And you really could not validate the connection was solid other than to cut the plug harness from the rest of your car, remove the switch,and connect your multimeter to it and work the switch with the connector connected to it on the bench. I replaced both the switch and the harness plug with aftermarket units and it seemed to cure the problem.