Question-Dick
The dimmer switch suggestion didnt work.All other lights work fine except headlights.------------------------
Followup To
Question -
I just came back from a spin this evening in the old 64 Pontiac and the headlights wouldnt come on.They were fine before.
The original manual speaks of a fuse for the other lights but all it says about headlights is to take it to my dealer if they dont come on.What to do?
Answer -
The headlights don't have a fuse, they only have the circuit breaker that is built into the headlight switch.
But your problem is probably not either of those things, most likely your problem is a dirty dimmer switch. Try this: turn on the headlights and see if the dash and tail light come on, even though the headlights don't. If that is the situation, then, with the switch still in the "ON" position, start clicking the dimmer switch - you might have to do this 20 or 30 times to rub the oxide off the contacts, but if it is going to work, you will see the headlights begin to flicker as you do this, (do it at night so you will see them), just keep it up and soon everything will come back to normal.
If, on the other hand, the tail and dash lights do NOT come on when you turn on the headlights, your problem may be in the headlight switch or the built in circuit breaker - you will have to get a meter or a test light and track down where the 12 volts isn't getting through.
I'm assuming it's the dimmer switch, though, so I'll quit here. If I'm wrong, ask me again and I'll try to help you troubleshoot the headlight switch.
Dick.
AnswerThe system just crashed and lost my previous answer, I think, so I'll type it again.
OH< well, I'll start over.......................
Since your tail lights and dash lights are working, we know that the low power circuits to the headlight switch are OK, but we still don't know about the circuit breaker that supplies power to the headlight bulbs themselves.
Before we dive into that, though, I'd like you to do one more thing regarding the dimmer switch:
Peel back the carpet from around the dimmer switch, and inspect the 3 wires that go to it. I believe your car has access to the wires from inside the car - you are very lucky, because on older cars, these wires are under the floor! Take your test light or meter probe, ground the black lead to a known good ground (the ignition key hanging in the switch is usually a good clean source of ground), and probe something that you KNOW has 12 volts on it, like the fuse box terminals. You do this to verify that you have a valid testing device - it should light up or show 12 volts or so on the meter.
Now, pull out your headlight switch and then take your probe and poke into the three wires on the dimmer switch. I'm betting you will find 12 volts on one of the terminals (coming from the headlight switch) but nothing on either of the other two terminals. If this is the case, your dimmer switch IS bad, and you can simply remove it and take it to your auto parts place to get a replacement that matches.
If I'm wrong, and you find 12 volts on two of the terminals, make sure your headlight bulbs are still off! If they are, you either have all 4 bulbs burned out, or a some wiring has come loose somewhere. Step on the dimmer switch to see if the bright light indicator is working on the dash, and then check the headlights again. If you still get no lights, but there is 12 volts on two of the dimmer switch terminals, the problem is forward of the dimmer switch somewhere. I think this is so unlikely that I won't take this branch of the solution any further until I hear back from you.
Back to another branch now: Maybe you'll find no 12 volts on ANY of the dimmer switch terminals. If this is the case, double check that your meter or probe is properly grounded by probing something hot on the fuse box again, and make very sure you have the headlight switch all the way out. Still no 12 volts!?!
OK< now we have to get serious; the next step is to check the headlight switch and circuit breaker.
Step one on this process is to drop the switch assembly down from the dash so you can see what you are doing. To do this, disconnect your battery, then pull the headlight knob all the way out. Now, reach under the dash and up to the top of the headlight switch assembly - feel around up there until you find a tiny, spring loaded plunger that goes into the top of the body of the headlight switch itself. Press this plunger down, and with your other hand, pull the headlight switch knob all the way out of the switch. This is a bit tricky, but keep at it, you'll get it out. Now, unscrew the trim ring/escutcheon around the hole that the knob came out of, and the whole switch will fall down behind the dash.
Pull it down to where you can see what you are doing, and find the circuit breaker. It is probably fastened right to the headlight switch - it will have a heavy wire going to one terminal, and the other terminal will be connected to the headlight switch. It is shaped like a minature metal bathtub, with two screw terminals sticking up out it. It probably has some writing on it, including the current rating (30A or 40A - something like that).
Now hook up the battery again, and verify that you have 12 volts on the heavy wire coming in to the circuit breaker from the main power buss in the engine compartment. If you do, next move to the other terminal on the circuit breaker - this is the one that supplies power to the headlight switch contacts that supply the dimmer switch and through that to the bulbs. If there is no 12 volts on this second terminal, your circuit breaker has failed. Disconnect your battery again, and remove the circuit breaker and take it to your auto parts store to match it up. You don't have to have an exact match, just get one with the same or slightly higher ampere rating, and mount it anywhere so that its contact cannot touch anything metal, and duplicate the wiring hookup from the old unit. Now, your headlights should be working.
Back to the circuit breaker test: If you DO find 12 volt on both terminals, reinstall the headlight knob into the switch, push it all the way in so it latches in there, then pull it all the way out as if to turn on the headlights.
Now, probe the "H" terminal on the switch - do you see 12 volts? Yes?
Are your bulbs lit? Yes? The problem is intermittent (Arrgh!), try wiggling things.
Bulbs NOT lit? The wiring from the "H" terminal isn't getting to the dimmer switch - follow that wire! Double check it at both ends - if you have 12 volts on one end and not on the other, there is something very strange going on - try bypassing the wire with another one, to see if that brings your headlights into normal operation. If so, you need to replace that wire.
If you DON'T see 12 volts on the "H" terminal, the switch must be bad. You can probably find a universal type at the auto parts store that will fit in the hole, but it isn't going to look right. If you want to use the car at night, you'll have to do that until you can find a correct switch.
I'm tired of typing, so I'll quit now - let me know what happens, please.
Dick.
