I have a 2006 Ram 3500 Diesel Dually with the tailgate light bar bulbs not lighting when applying the brakes.

1. Fuse #26 is good and the right & left tail stop lights (middle bulbs) light when applying the brakes.
2. Removed tailgate light bar, no broken wires and all three bulbs light when external power is applied to it's (male) harness plug.
3. There is no power coming from the other end of the (female) harness plug coming from the chassis wire harness.
4. Could not find any wire breaks in the harnesses.

??? If the brake switch supplies separate power to the tail lights and the tailgate light bar, could the switch be the problem?

Thanks.