i have a 01 f150 5 speed and when i shift from 3rd to 4th gear my air conditioner would go from blowing out the panel to blowing to through the defrost but know it blows through the defrost no matte where i but it to blow through the panel or any of other settings. what do yall thank is cause of it the blower motor or the switch.

 

The vacuum line that feeds the servo in the cab is broken, most times its near or under the battery. The servo or actuator is a vacuum operated motor that is spring loaded to the defrost position (Safety

 

The vacuum line that feeds the servo in the cab is broken, most times its near or under the battery. The servo or actuator is a vacuum operated motor that is spring loaded to the defrost position (Safety reasons). Find and fix the line and should be good to go.