I assume both high beam/low beam are out? Does the indicator for the high beam come on?
Power for the headlights comes from a heavy red wire protected by a fusible link. I don’t have a manual here, so I don’t know if anything else is protected by the fuse link. From there, it goes to the headlight switch. The headlight circuit is protected by a internal circuit breaker. Power comes out of the headlight switch on a light blue or yellow wire to the dimmer switch. From the dimmer switch power comes out on the light green (high beam) or light brown or tan (low beam).
if the high beam indicator on the dash works, you know you have power at least to the dimmer switch. That means the problem is most likely underhood. Start by checking for power at the dimmer switch on all 3 wires, they are arranged like this -_- . The lower middle terminal is going to be yellow or light blue and should have power anytime the lights are on. The other 2 will show power depending on low or high beam selected.
Hope that helps.