Well if that is happening that means that you have a load of some sort on your fans.

With engine off key out check to see if blade is spinning freely....

You may need to remove fan, dissasemble and clean.

I had lots of muck in mine. I took apart and cleaned with soap and water it was sooooo filthy and oily. I then used shop air to dry out and Degreaser from a spray can for fine cleaning. Then I put a drop of oil on bearings. Making sure not to get on brushes. Reassyembled and wala magic.

You could buy a new fan but pretty expensive. I would try cleaning and replacing resistor. I bought one at junk yard, with a lot of other stuff for 5.00. But if you just want the resistor might cost 20.00.

GOod luck again
Anthony Bridges