[paul2748]

The first thing I would check is power from the light switch to the dimmer switch. If you have power to the dimmer switch then check power going to the lamp themselves.

Wiring for the headlights is pretty simple. Power first goes to the light switch, from there to the dimmer switch and then out to the headlights, so trace the path for power all the way. If you have power all the way then check grounds.

Grounds are just as important as the power supply