Brake light problem 72 stepper

[Devins-step]

researched here and can't find a thread that gives an answer to my problem. As briefly as possible: Tail lights work, signal lights and emergency flashers work, brake lights work. When the brake is on and the left signal is on right brake light is good but when the right signal is on with the brake there is no brake light on the left side. So when I turn on the right signal and hit the brakes it seems to have no brake lights at all.... Thanks in advance for your help guys.
Dan

[cdowns]

run a ground wire from each taillight to the frame and see if that solves your problem with a good ground wire connected

[Bandit130]

This seems similar to my 72 C10 w/no brake lights. When left turn signal on, right rear brake light comes on. Right turn signal on, left rear brake light on when brake applied. Found that the turn signal cam, that the turn signal lever is attached to, has 2 contact plates on the under side on right side of cam. The contact plates have springs that apply pressure to plates to make contact with wiring harness contact plate. Contact plates were not being pushed outward evenly. Had to adjust plates just enough to be held in the assy. but spring out properly. All works now. I am going to replace turn signal switch as it is old and just needs new one. Hope this is helpful.