2007 Eddie Bauer -- Front AC Hot; Rear Cold

[Coastalplain]

Good Afternoon! (kind of)
I just replaced the compressor and accumulator on my 2007 Eddie Bauer v6, and hot air is coming from the front vents, while cold air comes out of the rear vents. If it was the opposite, I probably wouldn't have realized until I had friends in the back!

Oil and refrigerant were added per auto store spec (16oz PAG; 47 oz 134a); vacuum good.
Temp outside: 90F and humid; Low Pressure side: 40psi; High Pressure side: about 220psi (both a bit low)

The overall pressure appears a bit low, but the rear is cold and the front is hot. I've cycled everything on and off, from floor to defrost to all combinations and back, and cannot get cold air out of the front vents. Large tubes are sweating; small tube is hot.

Should they cool equally? Does this mean there is a valve somewhere that is closed? Are there electronics that may be causing the issue? Should I give up, have a cold beer, and call it a day? it is hot out.

Thank you for your help!

 

[MotorCityFats13]

I cant remember from back in the day when I was throwing the aux units in the back of the ford expeditions and navigators but I thought they had their own r134a system

 

[Flag Gibby]

All of the refrigerant for the system starts in the front, and the compressor works all the refrigerant in the system including the rear. The rear just has an expansion valve and an evaporator and I believe that's it.
If you switch from max heat to max cold on the front do you feel the temperatures change at all? Just wondering if one of the internal HVAC actuators is acting up and not necessarily the front expansion valve (orifice tube on the front I believe).

 

[Coastalplain]

Max cold and max heat, floor, dash, defrost and all combinations are the same in the front; all hot. Rear responds properly.

EDITs:
1) using a thermometer, I see that the air blowing in the front does change temperature. I couldn't tell the difference between 115 (cold) and 140 (hot), oddly.
2) This afternoon I've reread the gauges. Low pressure side is about 35; high pressure about 300 (temperaturer 95).
3) Finger on the actuator (driver side at about your knee/thigh) and it rotates, changing the temp (see 1 above).

 

[MotorCityFats13]

Is the heater core valve opening and closing when you turn on and off the ac... If its always sending coolant through the core it will over power the cold air... You can find it just before the hoses enter the core right side of engine

 

[Flag Gibby]

I am wondering if a wire/connector got knocked/taken off when you were replacing the accumulator and that is why the front is no longer cycling between heat and cooling. Before you go much further just make sure that the connectors on the AC system under the hood are firmly seated in place and no wires are damaged. Plus what MotorCityFats13 said.

 

[k1w1t1m]

Blend door actuator?

 

[Coastalplain]

Is the heater core valve opening and closing when you turn on and off the ac... If its always sending coolant through the core it will over power the cold air... You can find it just before the hoses enter the core right side of engine

Thank you for the reply. I located the valve, and before I started the arm was pointed down. After starting the engine and the rear AC cold (and a thermometer in the front seat vent reading 100), I checked again (maybe 30 seconds) and it was still down. I turned the AC of and on a few times, and it did not change. A couple of minutes later and after the engine was warmed up, the arm was pulled up (did not see it happen). Pulling the vacuum line off the top let the arm drop down again. The temperature out of the vents did not change, unless of course I turned the temperature up to where it went from 100 to about 120.

(the heater core valve is the same as the heater control valve, correct? I'm pouring through the FordParts diagrams to help out and that was the closest I could find)

 

[Coastalplain]

I am wondering if a wire/connector got knocked/taken off when you were replacing the accumulator and that is why the front is no longer cycling between heat and cooling. Before you go much further just make sure that the connectors on the AC system under the hood are firmly seated in place and no wires are damaged. Plus what MotorCityFats13 said.

Thank you for the reply, also. I checked all the connectors--just one off the accumulator and all the others around it. Nothing seemed out of line. I also replied to MotorCityFats13--see answer there for his questions, but I'm not sure which way the valve is open or closed.

 

[Coastalplain]

Blend door actuator?

Thank you--When I turn up the heat (leaving the AC on or turning it off), the temperature rises the same amount each time (about 100 to 120 right now). Seems to be working. I also put my finger on the actuator and it rotates as I increase the temperature.

 

[Coastalplain]

Is there an easy (relative I realize) way to get a finger on the evaporator or the heater coil(?) to see if it they are hot or cold? I can see the blower right under the glove box but I am not ready to get into the dash quite yet.

 

[MotorCityFats13]

The valve is moving so i guess it is working... Unless its leaking coolant through the valve and not redirecting it completely

 

[k1w1t1m]

Thank you--When I turn up the heat (leaving the AC on or turning it off), the temperature rises the same amount each time (about 100 to 120 right now). Seems to be working. I also put my finger on the actuator and it rotates as I increase the temperature.

The actuator I am referring to is by your right knee when you're driving. When they don't work sometimes you'll hear a clicking.

 

[Coastalplain]

The actuator I am referring to is by your right knee when you're driving. When they don't work sometimes you'll hear a clicking.

Yes, that was it. Worked smoothly and responded quickly to the temperature control.

 

[Coastalplain]

Thank you all for the responses--I have to get back to other work for a few days, but once I get on the HVAC system again, I'll put more information on the thread.

 

[Flag Gibby]

I hate to say it but I think that your front orifice tube, just before the evaporator on the outside of the firewall, is plugged and you are not getting any refrigerant flow through it. All the testing that you have done indicates that to be the most likely culprit, but difficult to pinpoint due to the fact that the vehicle has a dual AC system and the high side will not necessarily run too high.

Edit: Not sure what led to the replacing of the compressor and accumulator, but it is possible that if your compressor failed and put metal into the system that could have plugged the orifice tube or it could have been pieces of aluminum from the fittings/lines to evaporator getting into the orifice tube. Honestly the only way to figure it out is to capture the charge in the system and put a new orifice tube in since it makes no sense to not replace it when you need to inspect it and it's not exactly easy to get to.