I'd all so agree with that ^^.
Simple way to test is to use a test Light at the Socket and determine IF
you are getting power to the Bulb when in High Beam Position. IF you are,
then the Bulb is bad, if NOT, then check the wiring, and I'd stat that at
the Dimmer Switch. That could also be bad. If so, you can get a NEW one
from Auto Zone, or the likes. It's a real simple process to replace it.
(All so ~~~ Sometimes that switch just gets some Dirt on the contacts.
You could try Spraying it real good with Contact Cleaner to flush it out,
That just might take care of the issue, BEFORE replacing it.)