Head Light problem

[Guest]

I have all 4 high beams but as soon as I push the floor switch to put the low beams on all the lights go out. I put in A new high low switch and they still don't work I checked the power as soon as I click to low beam there is no power going to the lights does anyone have an idea of where to go next with the fix,
goldenbird

[simplyconnected]

Get your test light or meter out. Pull the Headlight Switch out, set the Hi/Lo Sw., to the low beams and check from ground to the sealed beam Red-Black terminals.

You may just have both headlights burned out. Yes, it happened to me and I swore that was impossible.

If you have no voltage at the bulbs, start tracing that wire back to the firewall. Eventually, it ends at the switch you just replaced. If so, you might have your wires crossed.

Red/Yellow 'feeds' the switch from the Headlight Sw.
Green/Black is high beams (one wire to the sealed beam, the other to the red dash light)
Red/Black is low beams (1958 Tbird has a 12amp circuit breaker after the pedal switch. '59 & '60 do not.)

Hope this helps.

Throwing new parts at the problem only leaves you with a pile of good parts you can't use. TEST the circuit and find the culprit. - Dave

[Guest]

I checked the wires at the plug as it goes into the fender there is no voltage on low beam and 12v at high. In checking the plug at the hi/lo switch there is 12v on 1 side and and no v on the other side . Where else should I look

[Guest]

This is on A 1960

[jopizz]

If your high beams work it means your headlight switch and the wiring to the dimmer switch is good. The problem can only be the wiring from the dimmer switch to the headlights or as Dave mentioned you may have two bad headlights. It's also possible your new dimmer switch is bad. It happens. You can use a jumper wire to bypass the dimmer switch just to be sure. You have three connectors in the plug. Find out which one of the three has 12v and use a wire to go from there to each of the other plugs one at a time.

John

[Guest]

I checked and the bulbs are good. In checking further when the switch is on high beam all 4 lights light up. When the low beam is on there are no lights and the wires start to get hot. I am thinking this could be A ground problem. I checked the ground at the fender well it has good clean connection. Does anyone know of any other ground locations for the lights?
goldenbird

[Tbird1044]

I sent Ray some simplified wiring diagrams to post to the TRL, but they are not posted yet. When I look at the headlight diagram, it appears there are 2 wires going to the headlights from the dimmer switch. One wire runs to the 2 low beam bulbs and the second wire runs to all 4 bulbs and is independent of the low beam wire. Here is where it gets a little tricky. The Low beam bulbs have 2 filiments in them and the high beam bulbs only have a single filiment. If all 4 bulbs light on hi beam, that means that the high beam circuit is okay and there is one wire running to these 4 filiments. When you switch to LOW beam, you are using the second wire and it is only connected to the 2 low beam filiments in the low beam bulbs. Since this does not work and you stated the wires are getting hot it would indicate that either this wire is shorted to ground between the switch and bulbs or one of the bulbs is internally shorted to ground. You could try and disconnect each low beam light one at a time and see if the other starts to work. If so, I would suspect a bad bulb. If not, then I would take an ohm meter and check to see if the positive wire running to low beam bulb is grounded. The wire to the low beams should be a red with black band. The high beam wire should be a green wire with a black band. Working in the industry for a while, we used to call bad bulbs "funny bulbs" and it was amazing some of the problems they could cause. I would pull the wires to the low beam bulbs one at a time and see if the other starts to work.
Hope this helps.
Nyles