It's a 2000 S-10 with about 67K highway miles and I hardly use the heater/AC fan above speed 2. Just this winter I noticed that when I would crank it up to 3 or 4 it would vibrate like their was alot of crap on the blades of the fan. (you know, out of balance) When I cranked it up to 4 the lights dimmed a little bit and it made a noise like it didn't want to go that fast (hesitating). Then when I tried it on 1 and 2 the damn thing doesn't even blow air. It only works on 3 and 4 and I still got that vibrating sound. Heater core is fine cause I got plenty of heat. I'd appreciate any help I can get cause my speciality is bikes, not mini-trucks. That and the last thing I want to do on my Christmas break is rip apart my truck. Also, for the entire time I've had the truck when you put the air discharge on the dash and use it for a while it would take a long time for it to shut off from the dash vents after you changed it. These problems are causing me to pull my hair out. :bash: Thanks in advance.