Problem with headlight/high beams.....need help

[trevor73402]

Hey all,
on my '84 when I have the headlightS on, on lowbeam both of the upper lights come on. When I turn on the high beams the lower lights come on along with the uppers, however the upper on the drivers side won't light up when on highbeams. The light comes on when on low, but when switched to high it goes off. Anybody know what would cause it not to light up when on high, but work fine on low? The other 3 lights work correctly as they should.

??????