help electrical problem!
It sounds similar to a problem I was having in my 70 Dart. My signal, running and brake lamps were all mixed up when turned on and I had no emergency flashers at all. Some were dim some were bright some flashed dim some flashed bright some not at all. Everything seemed to be completely out of whack.
One of the taillight sockets had lost it's ground to the metal housing. The sockets have no ground wire, they rely on making contact with the housing for their ground. The problem could also be the point where the housing is attached to the bumper. The sockets are pressed onto the housing. I lifted the edge of the socket and cleaned it up and pressed it back down and it worked for awhile and went out again. I fixed it and then the other side had the same problem. I soldered a ground wire to the outside surface of both sockets and grounded each socket straight to the bumper mounts. The wires are up under the bumper and invisible. I haven't had any trouble for over a year and it's my daily driver.
Here's what I did to check them, very simple: Take the lenses off the housings. Take a jumper wire or even just the tip of a slotted screwdriver. Make contact from the lip of the socket beside the bulb and then to the metal housing or use a jumper and go to a ground. If you see any change in brightness with the bulbs you have a ground problem. You may have a problem with more than one too. As soon as I grounded mine again it was like flipping a switch and everything worked as it was supposed to.
Now, you may have a different problem but this is a very fast and easy way to check the sockets and either fix them or eliminate them as the problem.
Oh wait, I'm sorry- 70 Duster. Lights in the tail panel. I'd still check all your grounds to those sockets. You'll just have to adjust the procedure.
