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Discussion Starter · #1 ·
The four marker/running lamps and front grill driving lights on my 70 Mach 1 do not work. Does anyone know if ther is a relay or some sort of central connection common for all of these lights. All other lighting electricals work on the car.


786 Posts
I checked my wiring manual. I don't know about the grill lights, but from what I can see, the marker lights should have +12v on one of the wires at all times.

The other wire is grounded by the emergency flashers and the turn signals - the grounding completes the circuit. The wirring harness runs along the driver side and has connectors at the left driver side kick shield, and inside the trunk or rear seat area. The license plate lamp is powered by the same 12v source. Thus if it is illuminating, your problem goes back to the grounding which is in the circuit I described above. I don't think from what I can see, this has anything to do with headlamp switch.

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