Everything but headlights

[Toro]

I've been working through all of my lights on my '72 and I now have everything working except the headlights. I can make them work if I jumper 12v from the fuse panel to the plug on the dimmer switch, so I thought it was that switch, but I jumpered across that connection and still nothing. I don't have voltage going g to the dimmer switch. I have replaced the main headlight switch, and the run lights, panel lights, brake lights, blinkers all work. I know the headlights themselves are good because they turn on when I jumper 12v to the plug at the dimmer switch. Does power normally come from the headlight switch to the dimmer switch and then to the headlights? Thanks

[Andy4639]

Originally Posted by Toro

I've been working through all of my lights on my '72 and I now have everything working except the headlights. I can make them work if I jumper 12v from the fuse panel to the plug on the dimmer switch, so I thought it was that switch, but I jumpered across that connection and still nothing. I don't have voltage going g to the dimmer switch. I have replaced the main headlight switch, and the run lights, panel lights, brake lights, blinkers all work. I know the headlights themselves are good because they turn on when I jumper 12v to the plug at the dimmer switch. Does power normally come from the headlight switch to the dimmer switch and then to the headlights? Thanks

Yes power comes through headlight switch to dimmer on the light blue wire. Then the other 2 wires are high/Low beams going out to the lights. Should be tan & green.

https://farm4.static.flickr.com/3645...c2a8064d_o.jpg

[Toro]

Ok, thanks. I don't have voltage on the blue wire at the dimmer switch. After looking at the wiring diagram, this should be un-fused straight from the headlight switch. It looks like the blue wire goes up from the dimmer switch and joins the wiring bundle that goes into the fuse panel. However, the wiring diagram shows it doesn't connect to anything in the panel, so it should just pass through in the wiring bundle up to the headlight switch correct? My next step tonight will be to trace the blue wire from the headlight switch to the dimmer switch.

[Wrenchbender Ret]

You are on the right track. The hot wire going to the light switch for the headlights is separate from the rest of the circuits so you may have to trace back from there.
George

[toolboxchev]

Have you checked the stupid little SFE 4 amp fuse on the headlight circuit located on the front of engine bay?

[RustyPile]

Originally Posted by Toro

Ok, thanks. I don't have voltage on the blue wire at the dimmer switch. After looking at the wiring diagram, this should be un-fused straight from the headlight switch. It looks like the blue wire goes up from the dimmer switch and joins the wiring bundle that goes into the fuse panel. However, the wiring diagram shows it doesn't connect to anything in the panel, so it should just pass through in the wiring bundle up to the headlight switch correct? My next step tonight will be to trace the blue wire from the headlight switch to the dimmer switch.

The blue wire simply "passes through" the bundle of wires at the fuse panel/bulkhead connector.. And just for the record -- there are no fuses in the headlight wiring.. The headlights and their associated wiring are protected by a circuit breaker built into the headlight switch..

Before you start tearing the wiring bundle apart tracing the blue wire between the dimmer switch and headlight switch, here's a more simple method of checking.. Unplug the harness from the headlight switch and the dimmer switch.. On the headlight plug, check for voltage on the large red wire.. Should be 12 volts... If you don't have voltage there, you probably have a bad connection where it passes through the bulkhead connector. .Or somewhere along it's length as it makes it way through the Harness starting at the battery positive terminal..

If you do have voltage on the red wire, put a jumper between it and the blue wire.. You should now have voltage at the dimmer switch plug.. If voltage is now on the blue wire, connect the plug to the dimmer switch and check for high and low beams.. If voltage isn't present, the blue wire is broken somewhere between the two switches.. Repair as needed.

You stated you have replaced the headlight switch??? Be sure it's a good one and be sure the terminals in the plug fit very tight on the switch

If you need a wiring diagram It's available in "wiring diagrams" thread located in the ELECTRICAL forum.. Also, a digital multi-meter and/or 12v test light will be very useful..