1999 Ranger 4X4 A/C issues

[caveman72]

i have a 1999 Ranger 4X4 manual trans. my problem is that the heater controls only blow out of defrost vents unless i put truck in 4 wheel drive then it works normally. I have traced to vacuum line from the heater controls out to the hub lock solenoid and found no leaks on that side and have replaced both vacuum lines to the hubs with no help. could some one please point me in the right direction on how to fix this problem so i could use the a/c.

 

[sgoff61]

My husband is having the exact same problem, which started immediately after replacing the lower ball joints on both sides. Anyone have any ideas?