natas
SDD Junior Member
howdy got a problem with my air in my cab i turn on my heat or a/c in any position and it blows out of the defrost and wont go anywhere else. is it a vacuum leak ? any help would be great 
Question 03 f350 air
- Thread starter natas
- Start date
DaveBen
SDD Senior Member
Vacuum leak and it is probably at the Automatic hubs. Look at the black lines going from the frame to the hub assembly.
Dave
Dave
roger2003
Full Access Member
I believe that your selector switch has crapped out or the positioning motor has malfunctioned. How much lift you got on your truck?
jestersv
7.3 addict
3x if its a 4wd but definately a vacuum prob. pump could be bad also need more info on the truck.
sagebel
Stock? Pfft!
Don't forget to check up under the glove box. There is a vacume connector up under there that your passenger sould have kicked. It is probably the hubs but checking under the glove box is pretty easy.
natas
SDD Junior Member
4 inch lift 4x4 just had the vacuum pump replaced last fall. i will go check the hub lines and under the glove box
Just found it on my '03 250. The plastic line running to the front hubs had fallen and burned through on the manifold. Fixed that and still didn't work. The switch on the passenger fenderwell seems to be leaking. I bypassed it with a piece of tubing and the pump shuts off. Guess I need a new switch.