The headlight circuit is separate from the parking light circuit. There's a fusible link on the starter solinoid - check that first. It then runs over to the right side of the firewall in the main harness, and through to the inside. There is a connector behind the glove box - I had a corrosion problem once with that connector due to a windshield leak. If I remember correctly, the wire is yellow (it's been years - Check the diagram) Then it runs accross the dash into the headlamp switch, which has an internal circuit breaker. From there it runs to the dimmer switch, and then out to the lights.
It's probably worth your time to check for power at the lights - I once watched a "technician" tear a car apart - and then his hair out, trying to fix the headlights - in the end it was two blown bulbs....It still makes me laugh