This is a big problem the fan that blows the heat out only runs sometimes. where is the fan and how do i fix it. It is 0 degrees out and its agravating. someone help me please!!!

http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/18/be/29/0900823d8018be29.jsp
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/18/be/29/0900823d8018be29.jsp

What a pain that is to do yourself. If you can get a good and reasonable mechanic to do it, don't hesitate... I'll never replace that thing in my blazer again. If it's anything like the 96 blazer you have to remove the computer and the coolant jug, and then cut through the black rubber box at the back of the engine compartment (passenger side) with a utility knife first (use caution because you have to glue it back together after you install the new blower motor). You have to take the passenger side front fender off to get the blower motor in and out, so you might as well do that first to allow yourself some room. Then just replace the motor and glue the rubber box back together (I'll never understand how they expect you to glue that thing back together correctly. (typical GM product.. I'll never buy on again))

Hope this helps.. It took me about two hours to do it, so you may want to take it in from the cold.

but the fan does run somtimes. do i need to replace it or what. any sugestions?

It could be a bad switch, motor, or connectors. I've found the connector at the blower motor gone bad causing this before. You can easily check the switch operation at the blower resistor connector.

If it runs only sometimes, it is the blower motor.