The blower motor on my 1998 GMC 2500 5.0 L works intermittently. It will come on randomly and work for a while and then cut off. It doesnt seem to be related to where the fan speed selector is set at. Recently it seems it he blower doesn't work far more then it does. I have replaced the resistor with no change noted. What should be my next course of action?

SOURCE: Blower motor or resistor?

If it was the motor that went out then it would not blow at all. The resistor is the culprit that starts killing off speeds. It should be about $25 to $30 at an aftermarket store like autozone or advanced auto parts.

SOURCE: my 1998 astro van blower motor only works on high speed.

No the motor is not bad or going bad, the heater blower motor resister is bad, thats regulates the blower speeds, its located under dash by heater motor 2 screws hold in heater box with a electrical plug to it.

SOURCE: Blower motor or resistor?

Yes its the blower motor resistor.

More then likley theres some trash or something in it, or possibly the motor itself is on it's way out. There not that bad to pull out of that body car, just pull it out and see what you can see.

The blower motor is under the glove compartment

You can replace the resistor on your own. Please find a detailed diagram which would guide you to do it.

http://autorepair.about.com/library/images/bl629a-lib.htm

Thanks

SOURCE: NEED TO REPLACE BLOWER RESISITOR. FAN ONLY WORKS ON HIGH SPEED

Under the dashboard on the passenger side you will see the blower motor. Near the blower motor inside the air duct is the resistor. It should be held in place by two screws. Hope this helps. Good luck

SOURCE: Blower motor or resistor?

I had a truck about the same year with the same problem, it was the wiring harness, but id check the resistor and the fan first before replacing anythings,