1983 Ford quits suddenly

1983 Ford f-100,2wd,aod,302 v/8. I was driving 55 mph at dusk,pulled headlight switch to turn on headlights and the truck immediately cut off,no noise or electrical odor...I have a good battery, but no D.C. anywhere..Where do I start??:

Start at the beginning, near the battery. If you are CERTAIN the battery is good, make sure both ends of both battery cables are clean and tight. Then check to see if you are getting juice through where the short positive battery cable hooks onto the solenoid.

If the other checks worked out I would next check the ignition switch.

Thank you for your replys..Trouble found,problem corrected..Trouble was in a connector located on inner fender next to the starter selonid..a poor connection with the largest of the 4 wires in the connector. this wire feeds a fuseable link and the connection would not handle the amps when I turned on headlights,would go OPEN instead..cleaned connector,applied silicon grease....