Need some info ,,, what year F150 do you have ??
also do you have poor air flow in all setting ,, floor, panel, defrost ,, or is just in one mode
we can go back and forth on this page
My truck is a 2007 ford f150 4x4 with 5.4 engine
I get good air flow on the feet/chest or just chest settings but not the other settings
ok,, on a 2007 F150 the doors in the plenum chamber to control air flow are controlled by three electric motors ,, there is no vacuum used
if there is a problem with the system and you have ATC,, push buttons to control your a/c ,,not three knobs like manual a/c ,, then there is a self test you can do on the system
so do you have ATC ,, buttons you push to control the a/c and heat ,, if so , I will tell you how to do the self test ..
There is a push button to activate the air conditioning and then three knobs to set fan speed/temp setting/air flow control
ok, so there is no ATC and you can not do a self test ..
I guess you can take a look at the main air direction motors on the left side of the dash , grab a flash light and get on your back in front of the drivers seat and look toward the center of the dash , up high ,, there you will see a electric motor , its called the mode door motor ,, as you look at the motor , operate the functions of the a/c from floor to panel to defrost and see if the motor is moving or anything is loose