1999 Expedition rear AC problem

When I have the front (main) controls on Max AC I actually get the air conditioning, but when I try to use the AC for the back I get nothing but hot air. I mean hot like I have the heater on max when I really have the
AC on as cold as it will go. Any suggestions as to how I can correct this would be greatly appreciated. Thanks in advance-CJ
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check blend door motor, they go bad a lot, gear inside motor strips
The motor on the side is for the hot/cold door

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hmmmmm, 1999 may be different
sorry bout that...........

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It sounds like a control problem. There is only one compressor and condenser, and since you have cool air at the front, it is likely the rear evaporator is also being cooled (I assume you have a system with the true rear A/C, not just vents in the back of the console). It seems likely that the blend door in the rear compartment is either stuck, or you have a problem with one of the controls. Unlike the main heater, the mode and blend doors in the auxiliary (rear) A/C unit are electrically operated. So it is possible you only have a blow fuse (check fuses 7, 23, and 24 in the main under dash fuse panel).
Does it make any difference whether you try the front or rear controls for the auxiliary unit? If not, I would remove the rear interior quarter panel trim so I could get at the auxiliary A/C unit to see if the blend door motor is getting power.
You should join the Expedition Owners mailing list and ask your question to that group (see http://xpog.com/mailman/listinfo/expedition_xpog.com ).You might all so ask the experts at www.flatratetech.com .
Ed White
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OR.. if like earlier versions, the back unit has a TXV (expansion valve) control. (and these play he!! with trying to fill the system by touch.. dont do it) This TXV could be bad or plugged... you need remove enough trim to see and touch the lines.
If the coils getting cold but not freezing, then it's fine and problem is blend door controls, etc.
If the coil's freezing then the txv is bad or the probe for it is not on the lo side line.
If the heater core is hot, check to see if the heat control valve in heater line is bad or disconnected.

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