AC ducting

[MrB]

before we got the truck back, the previous driver did something to the AC system that only allows it to blow through the defrost vents. ive taken apart the dash to replace the stereo with a factory unit i got from my friends 05 lariat and didnt notice anything wrong with the ducting in that immediate area. the AC is cold and the compressor doesnt cycle like crazy.

any advice you folks can give me to get the AC working back properly to where the selector can actually select where to blow the air? haha. i know its gotta be something simple. i just need to get the truck back to proper functioning form to get it in to the dealer.

any and all advice is appreciated.

[MikesF350ps]

Mr B,
Check for a vaccum leak, my son's truck had the samething that was found under the hood but not sure where

[Davey~do]

Look for a vacuum leak at the front hubs (assuming you have a 4WD). The rubber hoses are prone to dry-rotting and cracking where they attach to the housing. Also, the hubs themselves can develop leaky seals; check that as well if the first suggestion isnt the case.

[MrB]

so let me get this right, a vaccum line to the front hubs (yes i have 4wd) can cause the air conditioning system to malfunction?

ill check it out when i replace the left speed sensor. trucks throwing a code for the ABS light and turns out its either damaged wires (visual inspection looks good) or a faulty sensor. either way wheels gotta come off...