dale, based on what i've learned, there are 3 things that could be wrong.
1. fan motor blower
2. motor regulator
3. climate control unit
unfortunately, all three items cost big $$$ for parts and labor. when i mechanic replaced by fan regulator it costs me 4 hours in labor cost (2 hrs. to take out and 2 hrs. to replace back.) the same should be true with the fan motor. the climate control unit replacement is easy. but make sure it is the problem. good luck.