2000 Jimmy 4 wheel drive 4x4 problem

Ok hear is the deal. I have a 2000 jimmy 4x4. My 4 wheel drive is not working and the lights for the 4 wheel drive buttons arent lighting up. It has not been working for a year now but like once or twice a month I will start my car up and it will work untill i turn the car off again. I paid to get it checked out and they told me it would cost $1000 but the dealership seemed really shaddy. I cant remember what they said i needed. But the 4x4 service light stays on. Please if anybody can help me out. any info would help.

Here's some info to get started.
http://www.automotiveforums.com/vbulletin/showthread.php?t=572914&highlight=encoder+motor