The Stovebolt Site Forums The Shop Area The Electrical Bay Twilight Zone

Ok, first I would like to thank the helpful folks at the stovebolt academy. While replacing my master cylinder on my 57, this weekend I have been transported to an episode of the Twilight Zone. After replacing the MC I thought I had a stoplamp swicth problem and replaced that only to find out that's not it.
Here is the screen play man does a fine job replacing the MC, but when he steps on the brakes with the lights on the taillights and dash lights go out and there is a blue light from under the dash. Thinks he might have the stop light switch wrong (earlier post). Then he has no tail lights at all. Sends wife to NAPA while he's at work. Comes home puts new switch on, seems fine at first. Driving to work seems fine at first then starts to repeat problems of above. Comes home drops headlight switch and sees spark in tail light side of head light switch. Wants to get new one but he's unsure if that's the problem and why as it wasn't touch during removal of MC, so how can it be bad. Not sure of what to do for an ending want it to end like a Disney movie where it all fine, but need so folks to suggest an ending.

Thanks in Advance,
Mike

Sounds like the twilight zone indeed. I don't know if I can pinpoint the problem but I'll try by explaining the circuits you are dealing with. Your running/headlights and brake lights should be completely separate circuits. The brake light circuit...power is supplied to the brake light switch, which is closed when the brake pedal is depressed. The brake light switch is then connected to the turn signal switch where voltage is supplied to the rear brake/turn signal filaments, as dicated by the position of the turn signal switch.

For 1957 passenger cars (I don't know about the trucks), the front and rear running lights are controlled separately. When the headlight knob is pulled out one notch, both front and rear running lights should be on. When the headlight knob is pulled out all the way, the rear running lights should stay lit while the front running lights should be out.

All I can think of to explain what you are seeing is the possibility that the running light wire to the rear is getting pinched somewhere in the brake linkage and shorting out. This would explain why the running lights go out and the sparking at the headlight switch when the brake pedal is depressed. Also sounds like there is no fuse protection which is a bad thing. When I restore an old vehicle, I gut the stock wiring and completely rewire, with plenty of fuses to protect each circuit.