If what Bill said about neither high or low beams working on one side is happening, I would also check the ground wire to the inner fender. A complete circuit is needed for the lights to work.
The attached pic will help with correct wiring of the dimmer switch. Notice the "BAT" marking? That terminal is where the hot wire goes. The other two don't matter (one goes to low beam and the other to high beam.)
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
