1998 Jimmy headlight malfunction

The high-beams work, the running lights work, the tail and brake lights work, but NOT the normal headlights.
All of the fuses in the dash-panel are complete and the bulbs are fine as well. I had a problem with the brake lights failing but a few spritz's of compressed air to the hazard light switch on the steering column (as per instructions on THIS forum) did the trick.
Now, no headlights unless I need high's.
Any suggestions? I usually fix things that go wrong myself when I can, so any help would be MUCH appreciated. I couldn't diagnose it on my own and paying the local "electronics" garage to diagnose it through a computer is going to cost 80-plus bucks and the fix is usually in the hundreds $$$!!!
I'd like to fix it for the cost of the parts and some time after work if I could.
Any suggestions guys?

First thing I'd look at would be a failed dimmer switch.

Sounds like you blew the excess grease from the harzard all over the multifunction switch contacts - flip that blinker handle and see if it cleans up or otherwise....