4x4 ac prob

[greatwhiteford]

hi i have a 2004 f250 4x4 and one of the probs im having is when i turn on the four wheel drive switch if i have my ac running it goes from my vents to the defrost mode...
if you can give me an idea of what to look for i would appriciate it

[tech10002]

You have a vacuum leak somewhere in the 4x4 system if it only does it when 4 wheel drive is engaged. Check the vacuum lines down near the hubs. You most likely either have a broken line or the seals in the hubs are leaking.

[Blue01F250]

usually always a vacuum leak when 4x4 and A/C are mentioned together

[squeelpig]

2005/06 A/C or Ventilation Control Problems:
Trucks built between 9-15-04 to 6-8-05 may blow air out of the defrost vents with the mode selector in other positions. The vacuum pump may also run excessivly. Lower the glove box and inspect the vacuum lines to see if they are wraped around the panel/floor door actuator rod. If the hoses are wraped around the rod, inspect for damage to the hoses. If the hoses cannot be repaired, replace them with part number 5C3Z-19D699-AA for automatic temp control or 5C3Z-19D699-BA for manual climate control.
TSB 05-14-9.

[greatwhiteford]

thanks for all the replys my truck is in the shop right know for an oil leek on the back side of the motor an icp sensor is leeking and when i get it back i will take a look @ it and see where the leek maybe coming from