: Headlights won't come on



tommyhawk13
03-28-05, 12:10 PM
My headlights will not work.
They were working fine one day, and then quit. The parking lights and tail lights work fine.
I have replaced the headlight switch with a known good switch, replaced the dimmer switch with a new one, and checked all of the grounds. I ran a jumper wire from the pos battery to the light green wire on the low beam, and all four lights came on, so I know the grounds are good. I am also getting 12 volts at the light blue wire at the dimmer switch when it is not connected. When it is connected to the switch, I do not get a reading. Could this be a relay problem?

Fleet
04-12-05, 05:41 PM
That happened on my '71 Fleetwood Brougham about a year ago. All the lights worked except the headlights.

The mechanic had to do some work with the under-dash wiring, then it was fine.

I think it also needed a new headlight switch. The fuses were okay; I cheked those before taking it in to the shop.

DaveSmed
04-14-05, 08:55 PM
No idea on the wire colors at all. But the blue wire... Is that the power feed for the headlights coming from the switch? If the 12v suddenly disappears once connected, you have a high resistance point in the circut...somewhere. IIRC, the headlights (not the parking lights) have thier own feed from the junction block (possibly the starter battery terminal) through a fusible link, then the circut breaker in the switch. Unplug the headlight switch again, and if possible, figure out which wire has the feed for the headlights. Get a test light and your meter, and connect them to that feed. Ground the test ligth and the meter. (both meter and test light in parallell) With the test light on, what is the voltage at that terminal? If it is considerably less than what you started with, the little test light caused enough draw to drop the voltage. If it checks out, it could still be that half of the circut, since a test light is nowhere near the draw of two headlights. If it checks out there, try it at the headlight switch. I bet if you unplugged both the headlights, you would read 12v across the circut which is what makes this such a sneaky problem. FWIW, ordinarily I would suspect the headlight switch. But you replaced that.

Catillac
05-04-05, 07:21 AM
This just happened to my 82 Seville! I'm going to replace all my relays under the dash as I noticed that I have a Bauch relay. Everything else looks good. If this doesn't work, I'll replace the dimmer switch first, then the headlight switch. Easiest/cheapest first.

N0DIH
05-04-05, 01:27 PM
The headlights go through the dimmer switch too, and also I think there is a headlight relay and a auto restable circuit breaker too. Make sure it didn't come loose. Or the relay isn't bad.

Catillac
05-07-05, 07:53 AM
Well, it wasn't the relay... I replaced the Bosch one with a replacement and still no headlights... I'm going to replace the dimmer switch next, but that should be difficult as I have to try and get the old one out of steering column ):

Katshot
05-07-05, 08:09 AM
On those older cars, I always had problems with dimmer switches AND the connectors. They have a tendancy to melt and burn. Are you sure you're getting a good connection at the switch?

Catillac
05-07-05, 08:21 AM
Thanks for the advice Katshot, I'll look at the connector first...when I was driving, I had my high-beams on then when a car approached, I would flick them down, when I went to turn them back on, I had no lights. When I flicked the dimmer switch again, my low beams came on... so I guess it's obviously the dimmer switch/connector. I'll check it today.