Heat/air fan - she won't run Replacement motor - I don't even want to think about that.
Fuses OK? well then,
Here's another tip a swell mechanic showed me.
Due to the the way the windshield & wiper well scoops under the back of the hood...once in a while leaves and such will clog this area up, causing rainwater to spill over into the air con filter. Lots of water will soak the filter and it will drip down into fan motor. After a bunch of rain...and then if she sets for a few days, it causes to fan motor shaft to rust just enough to freeze up.
Usually you will notice immediately (July 120 degrees or December & no defrost. Panic...nope...this is EASY and cost nothing.
Only six screws are required to pull the wiper well cowling off. It looks like there are a lot of screws, but all the little ones hold the wiper assembly on the cowling. The BIG phillips head screws are the ones.
Lift up the cowling a little bit and you'll see the air con filter (directly in front of the passenger seat).
Pull out the filter and pull out any mess that may be on it... then...
Spray a liberal amount of WD-40 on the motor shaft...lots... Use a pair of pliers and twist the end of the shaft. 1/4 turn will free it up. Start up your air con and be sure the fan is running. Spray more WD-40 and put it all back together. DONE
Hope this helps.