1949 Dodge Coronet Headlights problem

[Guest nhranut]

I recently bought this car that is in pretty nice shape. The headlights don't work. The park lights do. I've investigated some and know the headlights has a circuit breaker. I know where that is at. How do I know if that device still works? (it is in a terrible place) Note: The battery was hooked up wrong when I got it (negative post was the ground) I staightened that out. Any ideas are welcomed.

[whtbaron]

If they didn't know enough to hook it up positive ground, is it possible that somebody boosted it with 12 volts as well? Just wondering if the headlights might have been blown out. Another culprit to check might be the dimmer switch. Being on the floor they could get badly corroded and blocked with mud and small stones. The light switch or faulty wiring is also possible. Get yourself a voltmeter or a test light and see where you have power.

Edited August 17, 2014 by whtbaron (see edit history)

[Rusty_OToole]

Could be different things. I would start at the headlights. Are they getting power? Are the bulbs good? Do they have a good ground? The dimmer switch is also a common source of problems.

[Bhigdog]

In any electrical problem the best place to start is at one end of the circuit and chase the volts. You will need any cheapo voltmeter or even a simple 6 volt bulb and a pair of alligator clips. Start at either the light switch or bulb and check every connection until the volts stop.............Bob

[37_Roadmaster_C]

+1 on what Bob said with one more thought...

I work in an electrical field and in most cases when troubleshooting a problem like this I would start where you know the power is good (battery) and work in a logical manner toward the end (lights). When you loose the power you then know the problem is between where you are now and the step before with power. The only other thing with this problem is that I would check for power at the headlight socket as it is quite common for the bulbs to be burned out because someone hooked up a 12 volt battery...

Robin

[Rusty_OToole]

Bad grounds and burned out bulbs too. I like to start from the headlight end simply because they are easier to get at, and a more common source of problems. You should be looking for frayed, broken or bare wires too.

[JACK M]

I would look at the dimmer switch as suggested. Easy to get to and problematic.

[Guest nhranut]

Thanks. Does anyone have a wire diagram? I have a digital meter. How do I use it to know/find a short if there is one? Put it to ohms setting? What number/s show a short? If it zeros out it's ok? Do those old circuit breakers function well? Fail often?

[Rusty_OToole]

If it was mine I would turn the headlights on and start testing. Switch high beams/low beams with the dimmer switch. Do either come on? With the light switch on does anything work? Headlights, tail lights, parking lights?

If NOTHING works I would suspect the light switch or the wiring to the light switch or the circuit breaker on the light switch.

If ANYTHING works that is a clue to where the fault is.

Do this test and report back.

[Guest nhranut]

First click does turn on the the front parking lights and the tail lights. When I turn it one more click that should turn on the headlights I get nothing. I assume the tail lights should stay on in the headlight position and the two front parking lights go off? While I had it in the headlight position I tried pushing the dimmer switch several times and still nothing. Does that circuit breaker just cover the headlights only or if the parking lights work, it's ok?

[Rusty_OToole]

Headlight switch is powered from a 30 amp circuit breaker. So if any of the lights work the switch is getting power.

Roll back the carpet and see if the dimmer switch is getting power (with the headlight switch on). Use the volt meter or a test light.