I recently replaced the blend door in my '99 f150 and after completing the job realized that the air flow (both cold and hot) now only comes out of the defrost vents (up top and down bottom) no matter what the switch is set on. the air will not flow from the panel or floor vents.

anyone have any idea what the problem may now be and where i should start looking before i start pulling the entire dash out again?

thanks, james

 

You probably lost your vacuum supply to the control switch/head unit.

Steve

 

that'd be nice, i guess. 'would be as simple as a disconnected or pinched vacuum line wouldnt it?