Rear A/C Blows Cold, Sometimes Warm, and Sometimes Hot..

[03ExFX4]

Recently purchased our 2003 Expedition XLT Fx4 5.4 about a month ago. During the test drives, everything checked out and did not come across and A/C issues or other issues for that matter. Truck was solid.

One day on a drive back home, I noticed the Rear A/C was blowing warm. Did some research and boiled down to two sources..

Either the Temp Blend Door is bad or Rear Air Expansion Valve is clogged.


I let the truck run for a bit and checked the Freon line going the the rear unit and the line was cold. Checked the rear A/C and it was cold. Rear A/C Blend Door does not make any noise and have not verified that it is actuating or not.

Air was good for a couple weeks and them became more temperamental. I have found that in the mornings and at night the rear air will blow cool/cold. However in the Arizona Summer Heat during the day, it will blow warm/hot, although sometimes cool/cold. Taken it to the dealer and the they provided same suggestions that it could be either the blend door or the expansion valve. I am not totally sold on those being the culprits and would like to see what others might think on the issue.

Did some searches and only came across issues where the Rear Air Blend Door was clicking or that the Rear Air was warm/hot all of the time. Could not dig up any temperamental issues.

Anyone else encountered a similar issue?
Possible thoughts?

Any advice/opinions are much appreciated.



Thanks,
David

 

[Bedrck47]

David in you post you state;
"Did some research and boiled down to two sources..
Either the Temp Blend Door is bad or Rear Air Expansion Valve is clogged.

Taken it to the dealer and the they provided same suggestions that it could be either the blend door or the expansion valve."

and now your on the forum and will most likely hear the same suggestions.

just because the blend door isn't clicking doesn't mean that's not the problem
If I were you I would remove the panel and check.

you can get all the suggestions but it will boil down to taking a look to see what's happening after all it is a 03 and things do start to fail

 

[Bedrck47]

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.

Auxiliary Climate Control Housing (Pic 1)

Item Part Number Description
1 19A706 Blower motor resistor
2 19805 Blower motor
3 19860 Evaporator core
4 18472 Drain tube
5 18476 Heater core
6 19E616 Temperature blend door actuator
7 19E616 Auxiliary mode door actuator


System Airflow (Pic 2)


Item Part Number Description
1 — Air inlet door
2 — Temperature blend door
3 — Headliner airflow
4 — Auxiliary mode door
5 — Floor airflow
6 18476 Heater core
7 19860 Evaporator core
8 19805 Blower motor

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 auxiliary mode 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 auxiliary mode 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 front 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 auxiliary climate control housing.

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 auxiliary climate control housing. 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.

 

[stamp11127]

Once you take the access panel off see if you can touch the expansion valve by hand. When it blows warm feel the line coming out of it, should be cold.

 

[03ExFX4]

Yes Roxy I understand where you're coming from.

I am more looking for any other owners that may have experienced the same problem and may provide input as to what resolved the issue.

Greatly appreciate the diagrams and detailed description.

Stamp, when I had first noticed the issue I checked the lines on the right rear underside near the rear tire and the line was cold. Would it matter which side of the line you would check? Being on the outside or the inside should not matter right?

I do recall at one time checking the line when the system was blowing warm and the line was warm. Hinting that it would be the TXV valve. Although, if it were clogged then it would be a constant heat. Rather than temperamental I would think.

 

[stamp11127]

Best to check after the expansion valve. If it is cold when it is blowing warm then it points to a blend problem and not a/c.

 

[03ExFX4]

Stamp,

Yeah that makes sense. So the blend door could still be faulty even though the gearing is not slipping? I'm kind of assuming perhaps that the door is getting stuck. Or that it is not responding to the temperature controls. I'll check that line out when I get home if the rear air is blowing warm today.

 

[Gruz7]

Stamp,



Yeah that makes sense. So the blend door could still be faulty even though the gearing is not slipping? I'm kind of assuming perhaps that the door is getting stuck. Or that it is not responding to the temperature controls. I'll check that line out when I get home if the rear air is blowing warm today.

Don't know if your problem was solved or not, or if you'll see and answer this question but I was wondering, seeing your name is 03ExFX4, if your fx4 model Expy has the center mounted skid plate on the frame just under the front row of seats.
If you have this skid plate, please do you know where you can get another one or where to get the bolts for one?
Thank you very much for the help, I have a '03 XLT but it has undergone, basically, an FX4 transformation with the installation of the front and middle skid plates, newly upgraded suspension and the black housing headlights have been ordered. I was wondering if you knew where I could find one of these plates because mine has been bent and now collides with my exhaust system and I snapped 2 of the bolts when I was attempting to get a rocky hill. (Still haven't lifted the truck).
Thank you if you can help!!!
Here's a pic if you needed more clarification what I am talking about....

Sent from my iPhone using Tapatalk

 

[GAINMOB]

Don't know if your problem was solved or not, or if you'll see and answer this question but I was wondering, seeing your name is 03ExFX4, if your fx4 model Expy has the center mounted skid plate on the frame just under the front row of seats.
If you have this skid plate, please do you know where you can get another one or where to get the bolts for one?
Thank you very much for the help, I have a '03 XLT but it has undergone, basically, an FX4 transformation with the installation of the front and middle skid plates, newly upgraded suspension and the black housing headlights have been ordered. I was wondering if you knew where I could find one of these plates because mine has been bent and now collides with my exhaust system and I snapped 2 of the bolts when I was attempting to get a rocky hill. (Still haven't lifted the truck).
Thank you if you can help!!!
Here's a pic if you needed more clarification what I am talking about....

Sent from my iPhone using Tapatalk

more appropiate to send a private message or ask on his member page...jacking the thread is very inappropiate

as they have said...the blend door could be stuck and the clicking is from the blend door actuator motors...when u take the panel off...you'll see the blend door and if its working will see it move upon selection...with the air temps u describe...cold in morning/night...thats when there isnt any sun...hot during the day...when sun is up...blend door to me would be stuck...and check for the things mentioned earlier

 

[Gruz7]

Very true, figured I'd have a better chance of reaching him through the forum... My mistake


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