a/c stuck on defrost
I am new to the sight and first time diesel owner 02 f250 7.3 crew cab 8ft bed, 122k with an 4r100. The truck is blowing air through the defrost vents with heat or a/c. I can adjust the temp no problem. The knob for air direction, vent, a/c, max a/c, off, works fine. I have looked online and this seems to be a problem with these trucks. The vacuum pump does come on and stays on as long the truck is on and does not turn off. Also there seems to be a tie between this problem and 4x4 auto hubs. I have manual locking hubs. I pulled the black hose off the solenoid and plugged it with my finger and the pump shut off. Seems to be a leak somewhere. That's my next move this weekend. I don't have the EATC, just old fashioned manual knobs for climate control. What do you think. Thanks for the help.