I have a 93 S-10 blazer. The fan would go off and on in different speeds without touching any switches. Now it doesn't work at all. Does anyone have any idea what might be wrong?

intermintent fault probably wiring, check fuse

i checked the fuse its fine

anyway you can get a wiring diagram maybe library here in phoenix they offer public version of ALLDATA

Check the blower ground for corrosion. Coming off the housing, bolting onto the firewall. (check both ends)

http://img.s10forum.com/album1447/aag.jpg