Head light question, Electrical Options

[KeithTurk]

Couple of quick questions. My headlight door motors work great but the headlights don’t come on. I happen to have another headlight switch that’s proven but it failed to fix the issue.

It’s on a 1974 914 If that’s relevant

Is there a headlight relay somewhere or something I should look at?

My turn signals flash quickly and I only have one brake light. Is it the same as the turn signal and the bulb just burned out? Hmmm ( I can check that pretty quick )

[ClayPerrine]

The headlights and the headlight motors are on completely different circuits that only have the switch in common.

Turn the lights on and turn them on high beams. Then see if you have power to the left 2 fuses on the fuse box. Then turn them on low and check the next 2 inboard and see if they have power. If neither of them have power, it is probably the relay that changes from low to high beam. It's a square metal can located on top of the fuse box. You have to take the mounting screws out and drop the fuse box down. It will be a square, silver can. It will have a red/white wire connected to pin 56 supplying power to it. With the headlight switch on, see if you are getting power there. The outputs come from pin F (high beams)and 56a (low beams). The yellow/red wire will come from the turn signal switch to change from low beam to high beam.


For testing purposes, turn the headlights on and connect the red/white wire to the yellow wire. That should light the low beams. Then connect the red/white wire to the white wire. That should light the high beams.

If all that works, then replace the relay.

[KeithTurk]

The headlights and the headlight motors are on completely different circuits that only have the switch in common.

Turn the lights on and turn them on high beams. Then see if you have power to the left 2 fuses on the fuse box. Then turn them on low and check the next 2 inboard and see if they have power. If neither of them have power, it is probably the relay that changes from low to high beam. It's a square metal can located on top of the fuse box. You have to take the mounting screws out and drop the fuse box down. It will be a square, silver can. It will have a red/white wire connected to pin 56 supplying power to it. With the headlight switch on, see if you are getting power there. The outputs come from pin F (high beams)and 56a (low beams). The yellow/red wire will come from the turn signal switch to change from low beam to high beam.


For testing purposes, turn the headlights on and connect the red/white wire to the yellow wire. That should light the low beams. Then connect the red/white wire to the white wire. That should light the high beams.

If all that works, then replace the relay.

. Wow clay. Thanks. Very precise info. I'll let you know how it works out

[KeithTurk]

Still no lights but the explanation gave me several outlets to check. Nothing yet but I have powered the lights with a jumper. I'm thinking it might be in the ignition switch because the fuses don't have power

[marksteinhilber]

Check the connections of the four small red wires at the battery. If you look at a wiring diagram you will see that these are the wires that provide power to a number of the circuits at the fuse panel. Jeff Bowlsby’s websire has the electrical wiring diagrams for the various model years. I have the diagram for my 74 printed out and labels written on the diagram so I don’t have to read the key to see what number each component is.

[ClayPerrine]

Still no lights but the explanation gave me several outlets to check. Nothing yet but I have powered the lights with a jumper. I'm thinking it might be in the ignition switch because the fuses don't have power

Do you have power to the red/white wire on the beam selector relay? If not, then you have a headlight switch issue.

[KeithTurk]

Still no lights but the explanation gave me several outlets to check. Nothing yet but I have powered the lights with a jumper. I'm thinking it might be in the ignition switch because the fuses don't have power

Do you have power to the red/white wire on the beam selector relay? If not, then you have a headlight switch issue.

No power to the relay. Going to find the 4 battery power wires

[KeithTurk]

Still no lights but the explanation gave me several outlets to check. Nothing yet but I have powered the lights with a jumper. I'm thinking it might be in the ignition switch because the fuses don't have power

Do you have power to the red/white wire on the beam selector relay? If not, then you have a headlight switch issue.

No power to the relay. Going to find the 4 battery power wires

[Front yard mechanic]

Not wanting to hijack this thread but I'm following to diagnose mine. I have power to the red|white wire when the switch is pulled but when I bypass the relay and hook up the white or yellow the voltage reading goes to zero? I've checked the continuity to the head lights and no problems now I'm stuck

[Front yard mechanic]

Figured it out the headlight switch was burnt. Changed it out and wala (IMG:style_emoticons/default/cheer.gif)