[Forkliftguy]

Do you get high beams at all? What's the voltage at the lamp sockets?

If there is voltage chances are the ground for the headlights is damaged, corroded or disconnected from the chassis, or on freak occasions two burnt out headlights at the same time (very rare).

If there is no voltage and since we know the switch is getting power (park lights work), I would work my way from there. Check and see if the there is power coming out of the switch for the headlights and move your way up from there until you find at what point there no longer is any power being supplied to the headlight wiring. Could be a faulty switch or headlight relay, etc.

Marc