I just purchased a 77 Vette and I noticed that the passenger side brake light is not working right. with the parking lights on the brake light goes out. Yet with the parking light off and you step on the brakes the parking light on the passenger side goes on and the brake light on the drivers side works fine, I have check the ground wires all are ok. Also if you take the bulb out of the driver side whilethe parking lights are on they both go out but if you take the passenger side bulb out the drive still remains on. Any Ideas.
Thanks Scotesr.

 

Welcome to the site scotesr. It sounds like you have poor ground(s). I would take out all of the bulbs front and rear and check the sockets for corrosion. Then make sure you have clean grounds. You can test it by running a temporary ground wire from each light to a clean ground. Good luck, let us know what you find.

 

Yes I thought of that right off, I have replaced the ground cable from block to frame and also added a ground wire from the socket to frame and still the same situation is still there. What I see thats weird is the fact if I turn on the flashers that the bulbs light up alternate on the rear but the front are ok. And in the rear the filiment lights up brake on drivers side rear and the filiment lights up parking light on pass rear, when the flashers are on.

 

If the sockets are in poor shape from rust, the bulbs may not be grounding around the perimeter. This could lead to the current seeking a ground through the filament and causing the lights to act as you describe. Try taking out every bulb, then one at a time put in a known good bulb and test the running lights, brake light, turn signal. Test each socket individually with only that bulb in place, you should be able to trace down the culprit.

 

Bought a universal socket and it works fine now thanks you

 

Glad to help.