Ok as you click the motor control higher and higher do you hear the fan running? Is there more and more air movement?
Most of these heater problems are the small blend motor.. NOT the major fan motor.. But they have been known to fail also.
If the fan motor is quitting on you the heat will get HOT anyway! If the blend motor is quitting you will most likely never get HOT heat. Or possibly never get anything BUT hot heat..
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

professional bovine relocation specialist