My airflow directional control is stuck in the defrost position. No matter which position I put the selector switch in, the air comes out of the window defrost vents. Switch turns the air on and off ok, but will not change selection. any ideas?

 

thay are controled by vacume so the fist thing i would do is se if you vac line form under the hood is still conected, were it gos thru the fire wall!

Make shore there isn't and air hissing under the dash!

 

Defrost is the default setting upon loss of control vacuum. IOW, the system will "fail safe" to the defrost mode when no vacuum is present.

Rusty

 

In the engine compartment I have good vacuum at an elbow just before it goes into the firewall. Is the selector switch just selecting different vacuum ports fed by the main line coming into it, in addition to an electrical contact to turn on the fan?

 

Yes, it's a vacuum and electrical switch. All the buttons have contacts for the fan, and 3 of them also have contacts for the A/C compressor.