andyboland

Please help me out! Left low beam out, Right high beam out, Left Brake light out, No turn Signals. Now truck will not even try to start. FCM/BCM replaced, but made no difference. What the heck is going on?

gmctd

Pull the taillites and park lites, check the bulbs for open, the sockets for oxidation\corrosion, clean as necessary, use ep chassis lube to weather-proof - also check the headlites and sockets for same - check the black ground wire that ties harness ground to the body for loose screw or connector

andyboland

Where is the harness ground?

cbrahs

TIPM

hope it isn't that. not cheap

gmctd

You'll find a black harness\body ground wire near each light position, attached to the fenders\bed with a body-screw, maybe even a spade-lug on the late trucks