Wiring Issue Headlamp not working Continued...

[ricker4444]

So, I tested to make sure I had power going into Z. It looks like Y is the hot feed to headlamp and X is like a return. I have power on Z but no power coming out of Y. Does the power from the battery go directly to the bulkhead connector and then come out of Y to feed the headlamp or does it feed the switch first and then power the lamp?

 

[OttawaCharger]

Remember that your headlight has high and low beam. 2 separate circuits. So not a return. Both those are independent. There should be another page that shows the cabin side of the bulkhead. You can continue to trace your circuit inside the cabin.
As for a "Return path" Your ground is your return path in a DC circuit.

 

[67Dart273]

The headlight circuit is dead nuts simple. The headlight switch has TWO power sources. The headlights ONLY are powered from a tap off the "welded splice" in the ammeter circuit, to a built in breaker in the switch. With the light switch full on, it feeds headlights power out of the switch, down to the dimmer. TWO of the terminals of the dimmer are ALWAYS hot with the switch ON. One terminal is power coming from the headlight switch, and the other is that power, selected by the hi/ low function of the dimmer, to feed out through the bulkhead and to the headlights.

The proper description for the dimmer is SPDT or Single Pole, Double Throw. This means it is switching ONE circuit (single pole) and selects which of two outputs which it feeds to (double throw)

IF THE power is getting that far, your cluster bright indicator should light when you actuate the dimmer.

The high and the low beam power, whichever is selected, flows out of the dimmer switch, through the bulkhead connector, and to the lamp harness in the engine bay.

THERE IS NORMALLY ONLY ONE ground for both headlamps, somewhere on / near the radiator support. FIND AND CHECK that ground.

You should be able to probe the two bulkhead connector terminals for the high and low beams and by actuating the dimmer switch, get first one and then the other to power up.

Next move to the lamps. Find the ground, pull out at least on lamp. Bad ground, miss wiring, or even both lamps blown. That HAS happened!!

 

[67Dart273]

If you examine your (darn poor) circuit diagram, notice the top lamp in the drawing, wire L9-18BK. This means wire no. L9, it is no. 18 gauge, and BlacK. Notice the eyelet connector pictured next to the lamp. That is the ground.

L3-18R going to Y of the connector and
L4-18BK going to Z of the connector are the hi and the low power feeds to the lamps, coming from the dimmer switch.

If you get into the service manual, and look up the instrument panel wiring, find the high beam lamp, you will see that it is fed with wire L5, and if you follow that back to the bulkhead connector at Y , you will find L5 and L3 on the same terminal. This means that L3 is the HIGH beam power going to the lamps

The only one left is Z and L4 so that has to be lo beams power

 

[67Dart273]

Last, starting a new thread "cold" is not necessarily a good idea. We have no idea without digging around for the old thread(s) what you have done, whether it's been re-wired, or hacked, or what you have tried, checked and replaced.

 

[ricker4444]

The headlight circuit is dead nuts simple. The headlight switch has TWO power sources. The headlights ONLY are powered from a tap off the "welded splice" in the ammeter circuit, to a built in breaker in the switch. With the light switch full on, it feeds headlights power out of the switch, down to the dimmer. TWO of the terminals of the dimmer are ALWAYS hot with the switch ON. One terminal is power coming from the headlight switch, and the other is that power, selected by the hi/ low function of the dimmer, to feed out through the bulkhead and to the headlights.

The proper description for the dimmer is SPDT or Single Pole, Double Throw. This means it is switching ONE circuit (single pole) and selects which of two outputs which it feeds to (double throw)

IF THE power is getting that far, your cluster bright indicator should light when you actuate the dimmer.

The high and the low beam power, whichever is selected, flows out of the dimmer switch, through the bulkhead connector, and to the lamp harness in the engine bay.

THERE IS NORMALLY ONLY ONE ground for both headlamps, somewhere on / near the radiator support. FIND AND CHECK that ground.

You should be able to probe the two bulkhead connector terminals for the high and low beams and by actuating the dimmer switch, get first one and then the other to power up.

Next move to the lamps. Find the ground, pull out at least on lamp. Bad ground, miss wiring, or even both lamps blown. That HAS happened!!

I will check these and post once I am done. Thank you for the information!