1981 GMC Sierra Headlight Issue

[81GMCSierra1500]

Hi all,

I have a 1981 GMC Sierra Classic, with the quad headlight front end, and I've just encountered an issue with my headlights. I'll pull the knob, and everything BUT my headlights will turn on... EXCEPT, when I have my high beams on, the top two headlights turn on to the regular low-beam setting. Just to clarify, when headlights are on W/O high beams, nothing is on, and when I turn the high beams on, the lower bank doesn't turn on, but the upper bank goes to it's "low" setting, and no "high beam" light comes on in the dash either... What's wrong!?!