Bought my 03 Expy EB new in April 2003. Took family trip 2 weeks later and when I tried to switch from rear heat to cool only got heat. Tried master control from front as well as controls from rear seats. No luck. Took to dealer twice with no luck. They say it is a known issue to Ford. They can manually switch from warm to cool for summer or winter but my controls don't work. Sounds like a blend door but no one seems to be able to pin down why the controls won't make it operate. Any ideas on the rear A/C would be appreciated.

 

Its amazing how many people get told "this is a known issue" but have nothing to really back that up. I havent seen a single service message on rear AC control problems nor have I had but one not working. I did have one that the control head for the rear AC was bad. It has a switch for roof vents and floor vents, blower speed and temp. If nothing is working then there is a problem they arent pinpointing. Some people make the mistake of attempting to control from the rear controls when the front switch is set for front control. The front swich must be set to rear control for the rear switches to have any effect.


Auxiliary Climate Control
An optional auxiliary air conditioning and heating system is available. The system is a one-piece unit that is located on the RH side of the vehicle between the side windows and the floorpan, behind the rear wheel well. The driver has primary control of the auxiliary air conditioning and heating system or can transfer control to a rear passenger control panel.

All of the auxiliary A/C-heater system components are serviceable from the inside of the vehicle except the lines

The auxiliary A/C and heating system has the following features:

The auxiliary A/C and heating system is functional whenever the instrument panel mounted A/C control is in any position except OFF.
The auxiliary blower motor recirculates the air inside the vehicle. Outside air is not available to the auxiliary system.
Air is cooled and dehumidified by the auxiliary A/C evaporator core only if the instrument panel mounted A/C control is adjusted to a position that requires A/C compressor operation.
The temperature blend door and the A/C damper door are controlled by electric actuator motors.
Movement of the auxiliary temperature control between COOL and WARM causes a corresponding movement of the temperature blend door to mix air flowing through and around the auxiliary heater core.
Movement of the auxiliary mode control between PANEL and FLOOR causes a corresponding movement of the A/C damper door to direct air flow between the panel (headliner) registers and the floor duct.

Blower Motor

The auxiliary air conditioning system contains a blower motor which is controlled by the heater blower motor switch on the front or rear auxiliary A/C control.


Control Assembly

The auxiliary A/C system has dual controls for the driver and rear passengers consisting of temperature, blower speed, and mode. The front auxiliary A/C control is mounted in the overhead console. The rear auxiliary A/C control is mounted in the rear finish panel of the front floor console.

Heater Core

The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer the heat to air passing through the plenum.

Evaporator Core

NOTE: If an evaporator core leak is suspected, the evaporator core must be vacuum leak tested before it is removed from the vehicle. For additional information, refer to Section 412-00 .

NOTE: Installation of a new receiver/drier is not required when repairing the air conditioning system except when there is physical evidence of system contamination from a failed A/C compressor or damage to the receiver/drier.

The evaporator core is an aluminum plate/fin type and is located in the plenum chamber. A mixture of refrigerant and oil enters the bottom of the evaporator core through the evaporator core inlet tube and then moves out of the evaporator core through the evaporator core outlet tube. When the A/C compressor is operating, air from the blower motor is cooled and dehumidified as it flows through the evaporator core fins.

Thermostatic Expansion Valve

The thermostatic expansion valve (TXV) restricts the flow of refrigerant from the high pressure side of the refrigerant system and separates the low pressure and high pressure sides of the auxiliary refrigerant system. Refrigerant entering and exiting the auxiliary evaporator core passes through the TXV through two separate flow paths. An internal temperature sensing bulb senses the temperature of the refrigerant flowing out of the evaporator core and adjusts an internal pin-type valve to meter the refrigerant flow into the evaporator core. The internal pin-type valve decreases the amount of refrigerant entering the evaporator core at lower temperatures, and increases the amount of refrigerant entering the evaporator core at higher temperatures.


Auxiliary A/C-Heater Lines

The auxiliary lines are secured to the underbody of the vehicle. Each auxiliary line is only available as a multiple-piece kit for ease of installation.

 

Thanks for the info. I cannot control the temp from either front or back. I can adjust direction of flow, either floor or headliner though. Last summer I had the dealership set to blow only cold air and then only heat over the winter as I waited for their "fix". Therefore, it sounds like refrigerant, heater core, etc work properly and this is a blend door problem. How does the blend door receive its commands from the temp control ***? Is the blend door assembly behind the right rear wheel well assembly? Many thanks!!

 

It is mounted on the rear plenum. It could just be a bad controller or its unplugged or even a broken door. The dealer needs to fix it, it is still under warranty. A problem at either control head or open circuit anywhere in the system could be the problem, to including a fuse possibly. I cant believe they cant fix it.

 

Thanks HW, they called this morning to say their man who worked on it last fall said it was a short in the wire harness. They are going to take it in on Monday while their regional rep is in and promise to trace the wire and fix it. They swear it is not the blend door, actuator, or anything on the unit itself.

 

Pappy, did your dealer get your vehicle squared away on this issue?

 

Yes, last week as a matter of fact. They determined that there was a short in the wiring harness leading to the rear blend door actuator. Apparently, a bolt from a rear seat belt had pierced the insulation and shorted the controls. They also installed the front A/C fix to eliminate freeze-up, shims in the body cladding to stop highway door rattle, new reversing side-mirror motors, new foam in both front seats that was shredding, new door latches and weather stripping, a fix for a window problem on the front passenger side, and today they are installing the fix for the rear differential. It turns out that every item on the list has a service message out on it. All are under warranty. Thanks for the follow-up and I hope this info helps others. This site is an invaluable tool for us Ford truck owners to stay informed.