Question about gm tailight wiring?

Question

gm ran 4 color wiring on all gm cars built what are the colors and what do they run mine are all dead and no blown fuse and no broken wire

Answer 1

brown = running/tail lights

yellow = left turn

dark green = right turn

light green or rarely,blue = back-up

Answer 2

Check the ground connections at the tail light sockets with a powered continuity tester on the ground in the socket with one lead and the other lead to frame ground.If bad take the tail light housing out and correct the problem.If their is no power check for power at the switch or at the harness plug in.