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!

  • Welcome to Motor Vehicle Maintenance & Repair! May 19, 2019 at 16:44
  • Not familiar with the zoning system on that vehicle, but it kinda sounds to me like an issue with blend doors that "activate" the rear zone. Assuming a single blower fan—if there are separate blower fans for front and rear that may not apply.
    – Huesmann
    Mar 1 at 14:47

1 Answer 1


Sounds like a faulty front blower motor or faulty front blower motor wiring. Try to disassemble the blower only and look for anything out of the ordinary. In the meanwhile avoid running the AC, because when a blower isn't working the evaporator may freeze up, and a frozen evaporator can soon turn into a leaking evaporator. The blower to the front evaporator is intended to always work, because i highly doubt the system/compressor would be able to handle both evaporators live but not transferring any heat and basically returning liquid refrigerant to the compressor (rear TXV is nearly always "nicked seat" or cross charged so that it never closes completely and still returns some oil to the compressor even when the rear blower is off).

Out of curiosity, is the expansion device an orifice tube for the front AC and a thermal expansion valve for the rear one? Or are they both TXVs?

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