Headlights on when battery is hooked

[Poncho]

I have a 1974 duster and the headlights are on when the battery is connected any ideas? The rest of the lights work with the switch. Disconnecting the light switch did not help.

 

[TrailBeast]

I would say either the switch is jacked or someone wired the headlights direct to 12v.

If you don't see any signs of being connected direct to battery power then it almost has to be a defective switch.

That's be my first diagnosis and the way I would approach it.

 

[67Dart273]

Are you saying that you completely remove the headlight switch connector and they are still on?

Either there is a melted cross in the harness caused by a short, etc, or wiring has been hacked.

You have a diagram? Shop manual?

 

[TrailBeast]

Are you saying that you completely remove the headlight switch connector and they are still on?

Oh crap, I missed the part about the switch being disconnected and them still on.

If that's the case the first place I would look is the bulkhead connector for melted wires and cross shorted wires.

 

[Poncho]

Are you saying that you completely remove the headlight switch connector and they are still on?

Either there is a melted cross in the harness caused by a short, etc, or wiring has been hacked.

You have a diagram? Shop manual?

I got a diagram last night then found all three wires to the dimmer switch cut. The bulk head connector on the cabin side looks good ( no melting ) and the engine and light harness under the hood is new. It seems that the harness has been hacked somewhere under the dash. Thank you

 

[67Dart273]

'Fraid so. If the dimmer has been cut, hard to say what was done. You can download a free '73 service manual at MyMopar, and there MIGHT be some differences between 73 and 74. One difference is that the 74 has the seat belt interlock. It might also help you to download the '72 manual, as the wiring diagrams are "shown" different. Up through 72, there were "line drawings" that is you could follow each wire from one place to 'other

In 73, this changed, to a completely different layout, which makes things harder to follow.

Also useful, are the separate wiring diagrams at MyMopar. These are often incomplete as to options, and sometimes leave out connectors, but they can be easier to follow

 

[JoeSBP]

I had exact issue in my '69 Valiant. Charge wire had overheated and melted into the harness energizing the headlight circuit.