My Husband and I just purchased a 2003 F150 Lariat. It was a seized vehicle, so it had been sitting for over a year before it could be sold. The agency had a put a new battery in it for us since we were driving it home from out of State. We were pleasantly surprised and fortunate that it seems to drive well and we had no problems on our 800 mile trip home...EXCEPT!... the heater only blows air out of the defrost areas, no matter what setting I put it on, floor, panel, etc. It's the push button climate control type heater panel. Does anyone know what might be the problem? Thanks!

 

See HVAC FAQs, link is in my signature.

 

there are several doors that move to direct the air up or down. THE doors are all controlled by vacuum cylinders. You have a vacuum leak. No vacuum, makes the system default to the defrost. You might have a bad hose from the mtor thru the firewall to the heater controls, or you may have bad o-rings on the controller itself. I have heard of a couple guys with the climate control system having o-ring leaks inside the controller and loss of vacuum.

 

https://www.ford-trucks.com/forums/9...-please-2.html

 

Thank you for all the great information! Unfortunately, I think the fix may be beyond our capabilities.
I showed my husband the replies and the schematic but he is still unsure of where these things are...like the EATC, etc. He's in his 70's and not use too working on this newer stuff.
Anyone live near Kalama, WA and fish? I build custom fishing rods and would trade one for a repair.
Dana

 

Have him check the easy stuff under the hood, it's pretty common.

 

Well, I underestimated our capabilities! We got the eatc out and replaced the o-rings (which were hard like plastic) and voila!...we have heat on the floor and the front panel! Thank you so much for the help!
Dana

 

GOOD NEWS.. Its nice to win one every now and then... Those little o-rings seem to be getting to be more of a problem every day...

 

I had the same problem with my 02. I am glade you got it fixed.

 

We couldn't have done it without the excellent information I found here!
Thanks again guys!
Dana