2005 western star high beams don't work on right side.

Check the pins for damage. Unplug the harness at the headlight and also where it splits from the main harness. Check for continuity in all of the wires. Check the main harness for voltage at the pins. If you're getting voltage and your wires are good, check the headlight assembly for damage.

Maybe you could swap the driver side harness with the passenger side if you don't have a multimeter handy. If the other side fails, open that harness and look for damaged wires.

 

Sounds like a broken wire in the harness. Look near the hood hinges, that section of the harness gets worn over time.