Howdy all I'm new to the forum , but have been crawling on F150online for a while now. Seeing as its finally warm enough up here in Montana (just cracked 65) I recently switched from "defrost" to "Max AC" and what I noticed is that the air still blew out only on the defrost vents up by the windshield. Knowing that this isn't normal, I was wondering if there was some way to fix this. Any ideas? Its a 2001 Screw 5.4L.

Jim

 

It's a really common issue.

Click on SEARCH and enter "+defrost + vacuum" for previous discussions.

Steve

 

Check your vacuum pump. Look at the HVAC problem thread above.

 

Any truck with a gas engine doesn't have a vacuum pump. Those are only needed on diesels.

Steve

 

I believe on the Fords (01 etc) the mode door was actuated by vaccum. I would check for a broke vac line near the firewall, its usually a brighter color like yellow or orange and will go through the firewall at some point.

I havent worked on to many fords (being they are of a better quality) so Im guess its vaccum operated.