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Virtual Technician
Virtual Technician, ASE Certified Technician
Category: Car
Satisfied Customers: 96
Experience:  25 years Experience. All makes and models, Shop Owner, Access to 4 repair databases. - I take the Opt Out Questions :)
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How do you control temperature in rear of van? Temperature

Resolved Question:

How do you control temperature in rear of van? Temperature seems to go full blast, as does the air conditioner. Fan controls work ok, but the temperature control does not work for back of van.
Submitted: 1 year ago.
Category: Car
Expert:  Virtual Technician replied 1 year ago.

Virtual Technician :

Hello, My name is XXXXX XXXXX I will try my best to help you with your vehicle issue. Do you have any warning lights on?

Virtual Technician :

Has there been any modifications made to this vehicle - wheelchair lifer, etc.

Expert:  Virtual Technician replied 1 year ago.

I see you are offline - Please contact me so that we may continue,

Thank you,

Rich

Customer: replied 1 year ago.

No modifications have been made.

Expert:  Virtual Technician replied 1 year ago.

Ok, I looked up the description & operation, which I have enclosed.

I just learned something new also!

Please let me know if you have any questions.

Thanks, Rich

DESCRIPTION AND OPERATION: AUXILIARY CLIMATE CONTROL Procedure SGML ID: N912105
SECTION 412-02: Auxiliary Climate Control 2011 E-Series Workshop Manual
DESCRIPTION AND OPERATION Procedure revision date: 08/21/2010

Auxiliary Climate Control

An optional auxiliary climate control system is available. The auxiliary climate control housing is located on the LH side of the vehicle behind the rear wheel well.

Control of the auxiliary climate control system is accomplished using the front (main) climate control assembly on the instrument panel. No auxiliary climate control assembly is present for the rear passengers.

Air Distribution

Vehicles with trim have a vertical duct that supplies air to the integral headliner A/C duct. Air is supplied to the passengers through six adjustable registers. The floor duct is integral to the side trim panel and has 4 fixed registers. The trim panel connects directly to the auxiliary A/C-heater unit.

Vehicles without trim do not have overhead registers or floor ducts. A unique register is used to distribute air-conditioned air and a heater outlet duct assembly distributes heated air.

System Airflow

The function selector switch (located in the front A/C control) controls the air distribution for both the front and auxiliary systems.

Airflow mode and temperature blend are accomplished using a single vacuum control motor which operates a single airflow mode door. When the function selector switch is in the DEFROST, FLOOR or MIX position, all airflow is directed through the auxiliary heater core to the floor outlet. Therefore only heated air is available from the auxiliary system when in the DEFROST, FLOOR or MIX mode regardless of the temperature selected for the front (main) airflow outlets.

When the function selector switch is in the VENT, NORM A/C, or MAX A/C mode, all airflow is directed through the auxiliary evaporator core to the overhead registers (if equipped) or the upper airflow outlet. Therefore only cooled air will be available from the auxiliary system in the NORM A/C or MAX A/C mode regardless of the temperature selected for the front (main) airflow outlets. Only ambient temperature air is available from the auxiliary system in the VENT mode because the A/C compressor is not operational in this mode.

The auxiliary system uses only recirculated air from inside the vehicle. Fresh (outside) air is not available from the auxiliary system.

Blower Motor

The auxiliary climate control assembly contains a blower motor. It is controlled by the blower motor switch on the front climate control assembly.

Heater Core

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

A/C Evaporator Core

The evaporator core is the plate/fin type. A mixture of refrigerant and oil enters the bottom of the evaporator core through the evaporator core inlet tube and is routed so it flows through the partitioned plate/fin sections. Refrigerant then moves out of the evaporator core through the evaporator core outlet tube.

Thermostatic Expansion Valve (TXV)

NOTE: The Thermostatic Expansion Valve (TXV) is not separately serviceable. It is serviced only with the evaporator core as an assembly.

A TXVregulates the flow of refrigerant into the auxiliary evaporator core. It is also the dividing point in the auxiliary portion of the refrigerant system between the low- and high-pressure sides.

The TXVincludes a temperature sensing bulb which measures the temperature of the refrigerant in the suction line and transmits it to the TXV. This temperature variation regulates the refrigerant flow to the auxiliary evaporator core.

  • When the bulb senses a high temperature, the TXVopens to increase refrigerant flow through the auxiliary evaporator core.
  • When the bulb senses a low temperature, the TXVstarts closing to decrease refrigerant flow to the auxiliary evaporator core.
Customer: replied 1 year ago.


Still on line? Can we communicate by chat, or whatever? How do we talk? My question still remains because I am concerned that the front temperature control has no effect on the back temperature. It does on the front, but not the back.

Expert:  Virtual Technician replied 1 year ago.

Hello,

This site e-mails me when you reply. :)

Maybe this will help - the front temp control DOES NOT control the rear a/c or heat

What determines the temp of the air in back is what position the the outlet (function) knob is on.

Hence for heat: "Therefore only heated air is available from the auxiliary system when in the DEFROST, FLOOR or MIX mode regardless of the temperature selected for the front (main) airflow outlets."

``````````````````````````````

If you want A/C: When the function selector switch is in the VENT, NORM A/C, or MAX A/C mode, all airflow is directed through the auxiliary evaporator core to the overhead registers (if equipped) or the upper airflow outlet. Therefore only cooled air will be available from the auxiliary system in the NORM A/C or MAX A/C mode regardless of the temperature selected for the front (main) airflow outlets.

``````````````````````````````````````````````

They did this system weird - the temperature in the rear is controlled by the FUNCTION control not the Hot/Cold knob.

So really the only way to control the rear heat is through the rear fan control.

(Blower motor)

I'm not a big fan of this system.

Customer: replied 1 year ago.

So it is full heat or full cool in the back when the fan is turned on. There is no temperature control in the back is that right? You either burn the passengers out or freeze them out and turn the fan off and on quite frequently.

Expert:  Virtual Technician replied 1 year ago.

Unfortunately - yes.

It all depends on what function you are on in front that determines the hot/cold to the rear and then you adjust the rear with the fan.

Sorry.......Not a very good system......

Expert:  Virtual Technician replied 1 year ago.

I did some checking, and there might be an after market company that has a "controller".

They are not sure because it is so new but they are looking into it.

I'll let you know what they say.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Expert:  Virtual Technician replied 1 year ago.

I just received an e-mail from Bruan-

without extensively re doing the rear heat/ac system - they do not offer a "kit" for this model vehicle.

Virtual Technician, ASE Certified Technician
Category: Car
Satisfied Customers: 96
Experience: 25 years Experience. All makes and models, Shop Owner, Access to 4 repair databases. - I take the Opt Out Questions :)
Virtual Technician and 16 other Car Specialists are ready to help you

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