resistor or blower???
 

Intermittent issue - sometimes no fan at all - at any setting. Sometimes works fine. Other times it starts off ok, but after a while kind of peters out - hit a bump and it cuts off... 20 minutes later, hit another bump and the fan starts up again. I'm suspecting the blower - if the resistor goes out, shouldn't it still work on the high setting since there's no resistance function going on) or is that faulty logic on my part? Sound familiar to anyone or any easy way to tell - guess I could check voltages coming out of the resistor when things aren't working - if that looks normal it would be the blower - other thoughts?

If it works on an off- especially on bumps it'll be ur blower

I second the motor is bad.

Bad resistor you only have 'full blast' and off in all other positions....

Intermttent is typically the motor. Possibly bad wiring (check ground) but if the car is in good overall shape (not a lot of corrosion) it is probably a bad motor...