QuestionHi Dick! I don't know if you can help with this, but here's my problem: I have a 1957 Chevy Bel Air with a rear end wiring problem. The only lights working in the back end are the turn signals - they both work great. The brake lights, parking lights & license light all don't work. I know there's power somewhere in the back since the signals operate as they should, but all of a sudden I lost every other back light (all the front lights operate as they should). I checked my plug connections and shook the wiring to see if I had a short, but got nothing - not even a flicker in the back end. The bulbs are new LED's, so I know they work.
Any idea on where to look for the problem? I hope I gave enough info - please let me know if I didn't.
Thank you very much for the help!
Greg
AnswerI don't know if the conversion to LED's has affected any of the wiring, so I am going to answer as if this modification had not been made - I have no idea what was done to do this and any guesses I'd make would probably be wrong.
You have two separate problems here - we'll get after the brake lights problem first.
Find the brake light switch - it's probably on the master cylinder - it will be the only thing on the master cylinder fluid lines with wires going to it. Take the two wires off the switch (they just unplug) and connect the two wires together while someone watches out back for the brake lights to come on. If they do, you have a bad brake light switch. It is possible your car has a mechanical (not hydraulic) brake light switch, 57 was a changeover year. If your car has a mechanical switch, it is up under the dash, positioned so that when you push the brake pedal down, a spring loaded button is released, turning on the brake lights. Either way, it will have two wires, connecting them together should light the brake lights. It is possible the key has to be on for the brake lights to work on your car - I doubt it, but check both ways to be sure. If the brake lights still don't come on when you connect the two wires from the switch, then we go to the next step:
The brake light fuse (which may be a separate one from the one which supplies the turn signals) is probably either blown, dirty or loose.
Look in your owner's manual to see which one is the brake light fuse - usually that fuse will take out the dome and instrument panel lights also when it blows. You don't mention if those are working - if they are, then it probably isn't that fuse.
If you do not have the owner's manual or the shop manual, you'll have to slither under the dash, find the fuse block, and take your test light or meter and check for 12 volts on both ends of every fuse. The key has to be on to make some of these checks. Don't make the mistake of just checking the metal ends of the fuses, also check the spring clips that hold the fuses. These cars are famous for developing crud on the inner surface of the spring clips such that the fuse checks out OK, but is not actually making electrical contact with the spring clip.
If none of the above brings on the brake lights, then take the car back to whoever modified the rear lights and ask for help - since I don't know what was done, I can't help you.
The parking lights, front and rear, and the license light are on a different circuit and use different bulb filaments, so that would appear to be a separate problem. This could also be a fuse, or it could be a problem in the headlight switch. The first thing to do is have someone watch the tail lights for a flicker of light while you play with the headlight knob - moving it slowly through the park and headlight on position, to see if they even flicker while you fiddle with the switch. If they do, you need a new headlight switch. If there is no life at all from the switch, you'll need to get under there and poke at the terminals on the switch with your test light to see if 12 volt power is coming in to the "B" terminal. If it is, yet there is no power on the "P" terminal when the switch is pulled out, the switch has failed. If there is no power on the "B" terminal, you're back to the fuse block again - just follow the wire from the "B" terminal back to the fuse block to see why you have power on one end of it and not the other.
By the way, the headlights themselves are on a totally different circuit, so don't bother telling me the headlights are OK, it doesn't matter.
Good Luck, I think you're going to need it!
Dick
