I just bought a 2005 F250 Crew Cab 4WD last week. New to Ford trucks, new to FF.
I was messing around this afternoon, "getting to know" the truck and found that when I shift the (auto) switch in to 4H the A/Cgoes to defrost. It stops blowing towards the caband starts comming out the top towards the winshield. When i turn it back to 2h about 10 seconds later it comes back to A/C.
Was looking through the ownersmanual and nothing is mentioned about this.
Is this normal, or do I needto start looking for another issue?

 

The vacuum motors/pots that control the venting positions orselections are controlled by vacuum.. The 'default' position for the vents is the defrost position.. The ESOF 4x4 hubs are lock controlled by high/lowas well.. Ifeither the hub seal/s or lines leaks, or the vacuum pump on the right/passenger inner fender doesn't operate correctly the vacuum reservoir will or can be depletedfrom the stored/available vacuum and the vents will then switch to defrost.. Check to make sure the vacuum pump runs when the vent positions are switched 'back and forth' (will help exhaust the stored vacuum) or when the reservoir tank or pump outletconnection is removed, and that the lines at the 4x4 hubs, and the connections in the wheel well area are tight and connected..