97 rodeo 4 wheel drive wont engage! help!

About 2 years ago my 4wheel drive indicator light in the dash started flickering. When it was put into 4 wheel, the light would come on fine, and when it was taken out, the light would remain on for a few days, then start to flicker intermittently... Eventually the light went out all together earlier this year...

Just went to use 4 wheels for the first time this year (worked ok last year), and NO 4 WHEEL DRIVE! When I put it in 4 high,I can feel the transfer case engage, but that is it. same thing in 4 low, everything feels right with the lever, but the front wheels are not spinning... Anyone have any thoughts or experience with this? Could this be an electrical switch or vacuum problem? I have maintained this vehicle meticuloulsy since new, and have had relatively few problems until now. Your help is appreciated in advance!!

Here's a thread that may be of some help - http://www.automotiveforums.com/vbulletin/showthread.php?t=348134&highlight=4wd+indicator+light
maybe the mechanical portion of the switch might need adjustment, cleaning, or check the vacuum lines for cracks or damage? It's located under the skid plate - fairly easy to see with the plate removed.
highlandlake