Here in NW Arkansas, I don't need 4WD often. Last week, I was dragging a trailer up an incline, rear started to spin, so I engaged 4WD to assist. Cold air stopped coming out of the vents, 95 degrees outside. (But the blower could still be heard.) When I got home, I checked every fuse inside and under hood. All good. Then - in 2WD - AC started working again. I have never used the 4WD in summer, so I have never seen it happen. Question for the Knowledgeables here: Do the older pickups stop the air con when 4WD is electrically engaged? Perhaps to allow all power to the drivetrain? (I did not lock the front hubs.) If not, any ideas about this would be extremely welcome. Thank you.