Chevman32,

Because the the brake is also the turn, the problem could be in the turn signal unit itself as well as the taillight assembly.

You have the left one working so it can act as your 'demo' while you troubleshoot the right side.

Assuming all the wires are intact, you need to see if the brake/turn signal is making it back to the light, which means the turn signal unit is OK and there is something wrong with the ground or lamp assembly..OR, it isn't making it that far and the problem is in the turn signal unit itself.

A voltage tester or ohmmeter can help you find out how far your signal is making it. This will narrow the search...it's either up front or it's in the back. Make sure your taillight assembly is well grounded to the bed and frame.

Stuart