Yesterday my wife noticed her Cougar was not putting any air out to defog the windshied. I took a look and noticed it would not put air out anywhere. Took out the glovebox to look at the fan...the fan runs at its various speeds but none of the solenoid valves opens. Basically the fan is trying to blow into an enclosed chamber causing the fan to make strange noises. With the glove box out I was able to manually move the solenoid for the windshield and air came flying out like normal...nice and strong.

What could cause all positions to not work at once? I noticed that the solenoids that control the positions are all vacuum controlled. Is it possible the vacuum is not working causing all to fail? where in the engine bay does the vacuum come from and where behind the dash is the solenoid that allows the vacuum to be applied to each of the vacuum controlled "flapper" for the different positions?? Is there a fuse that only has to do with position control???

Any help appreciated!

THANKS