A/C Problem - Electric or Vacuum?

[jammmm]

My A/C is cold....but my switch to turn it from off to vent to A/C to Heat, etc. will only blow out of the Defrost and floor.

Okay....my center dash is out and the glove compartment is off. I can't find a vacuum leak anywhere. I've been told it may be an electric motor which switches the doors from vent to defrost. I really don't know.

Any suggestions? If it is a motor....where is it?

Thanks in advance for your help!