Stuck on defroster

Check for vacuum leak in the lines and around the switch
check vacuum source

Open hood and try to locate a disconnected vacuum line
and if you like to have some one to take a look at it for you it shouldn't take more then an hr top

TO: All

Could be that the defrost door is binding or a disconnected vacuum hose at the air damper door vacuum control motor or the motor itself.

Good Luck

Sounds like the vacum actuator is broken or leaking might or might not be controlled by the switch. It could be hooked to the air door by a rod that might have come loose. Check there.

The mode selection is done through a series of air doors that are operated by vacuum. When there is either a partial or total loss of vacuum, the system will default to either defrost or on some vehicles, heat. Acceleration can also have an effect on the doors for the same reason.

Look under the hood for a small black plastic hose coming through the firewall. Follow it to the vacuum source looking for any breaks, cracks or leaks. Also follow any other lines that branch off because they may go to a vacuum reservoir (storage tank) and a leak there will cause the same problem. Using a vacuum gauge to determine if you have full vacuum at any given point is the best way to find it. You can cut into the line anywhere and splice it back together with a piece of vacuum hose. Find the broken line, you found your problem.

Maybe lost vacumn source from engine or select switch faulty. Need to pull controler out check for vacumn on black hose.

You are looking for a vacuum leak. The vent doors are actuated by vacuum. If there is a leak, it goes to defrost and floor.

Check under the dash for leaks as well as under the hood.

Check for vacuum leaks
start at the source under the hood