I have a Ford e350 van that does not blow out the dash vents but bows in the rear. The AC compressor is engaged. If I have the rear AC off and the front on (not blowing of course), I can get it to turn on if I run over a bad bump on the road. If I turn on the rear AC (they both work off the same compressor), the front AC turns off. This condition is repeatable but I, of course, don't want this to be my "solution".
Any ideas and debugging would be most appreciated. Thank you!