I just bought my 02 supercrew a month ago and I cannot get the heating/cooling system to change vents. It comes out the main vents in the dash that point at your face, but will not change to the floor, or the dash when I press the defrost button. Didn't notice during the summer, since it's nice to have the AC on your face...but now I'd like to defrost my windows!

Any ideas other than to take to the dealer and make their next boat payment for them to tell me what's wrong...

 

As a test, locate the single balck vacuum line that runs through the dash to supply the HVAC controls. It's usually between the battery and the firewall. Disconnect and plug (engine side) the line and see if your airflow is now out of the defrost only. (We're checking to see if the system drops into fail-safe airflow).

Give that a try and see what happens.

Also, check all postions and see if there is any switching of the airflow at all (vacuum line connected properly).

Steve