The Stovebolt Site Forums The Shop Area The Electrical Bay 1951 3100 Headlight issue 12V

Assuming the other headlight worked on both high and low beam before installing the new H6204 the problem is with the dimmer switch or the low beam wire from the dimmer switch to the terminal board near the front of the drivers side inner fender sheet metal.

Quick test: Aim your truck at a nearby wall. With the headlights off, use a jumper wire between the hot wire on the brake light switch and each terminal on the dimmer switch. One terminal (the headlight switch voltage feed) should do nothing, one should light the high beams and one should light the low beams.

If both side high and low beams come on, the dimmer switch is bad.

If high and low beams work on the drivers side, but not on the passengers side either the passengers side headlamp is bad or the wiring between the drivers side terminal board and the passengers side headlamp socket is bad.

If high and low beams work on the passengers side, but not on the drivers side either the drivers side headlamp is bad or the wiring between the drivers side terminal board and the drivers side headlamp socket is bad.