I've just read gobs of old posts but can't seem to put my finger on the problem I've recently started having with the dual zone HVAC.

A few weeks ago the A/C started blowing a little warm and a little warmer each time I took the car out to the point where now it's not even cool.

The A/C has never been serviced so I figured I'd get the freon checked. Had that done today and all was well. All pressures were perfect so it didn't need freon. I figured maybe it's the actuators from what I've read here on the forum.

I get home and check for codes. No codes related to the HVAC and all the dual zone controls are working fine as far as diverting air to each setting. Fan controls are fine too. I pulled the #27 fuse and reset everything and still no cold air.

So I'm stumped and don't want to go to the dealership. Anyone got any ideas why I'm getting warm air when there is freon, compressor engages, controls seem to work and the actuator doors appear to be indexed correctly???? Prior to this the A/C has been flawless and ice cold.

EDIT: add on questions...Is there a central dampener door from the heater area that could be sticking open? Does anyone have a "cut-away" pic of the HVAC under dash ductwork??? Thanks!

 

I don't know why the A/C is doing that, but I will ask around for you.

 

Thanks!

 

Hi, on the dual zone system the temp is controlled by the control head signal to the actuator motors which control the actuator doors. There are 2 doors, one for passenger, and one for driver. They are independent of each other. Air enters the car from the outside vents, through the recirc/outside door, and then through the heater core which is always hot when the car is warmed up, at that point the actuator doors directed by the control head temp settings, determines whether to divert the air from the heater core to the ac evaporator coil fully, or a mix, or allow straight heat.
The reason for your problem could be attributed to a few possibilities.
1, Refrigerant level, I know you said it was checked, but you have to be sure, a lot of shops make mistakes on the proper levels. Post your hi and low pressures @2000 rpm's and the outside temp. [Read "plasticfans" thread on ac charging].
2, The outside temp sensor or the inside temp sensor may be bad, does your outside temp display read accuratly.
3, The control head may be bad, it needs to be diagnosed.
4, The actuators may be broken, or stuck, or the actuator motors may be bad. This is a remote possibility, because they both don't usually go bad at exactly the same moment.
5, The Compressor isn't running or the internal valves are bad, you said it was running ok.
6, Restriction in the system, this would show up in the pressures.
7, Extremely dirty condenser, this would also show up in the pressures and most likely shut the system down when the pressures got high enough.
My first action would be to absolutely confirm the refrierant pressures are proper.
Secondly I would run a diagnosis in the control head--SEE BELOW.
GOOD LUCK

==================================
Too Hot in Vehicle
Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step clears the HVAC control module memory and checks for current air temperature actuator diagnostic trouble codes.

Ambient air temperature must be above 3°C (38°F) in order for this A/C Compressor test to be run.

The specified values are from the A/C System Performance Test

Step
Action
Values
Yes
No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The temperature cannot be adjusted, or the cooling is insufficient during A/C operation.

1
Did you perform the HVAC Diagnostic System Check?
--
Go to Step 2
Go to Diagnostic System Check - HVAC Systems - Automatic

2
Recalibrate actuators. Refer to Re-Calibrating Actuators .
Install a scan tool.
Turn ON the ignition, with the engine OFF.
Observe the Diagnostic Trouble Code (DTC) List in Heating and Air Conditioning.
Does the scan tool display any DTC B0361, B0363, B0365, B0367, B0441 or B0446?
--
Go to Diagnostic Trouble Code (DTC) List
Go to Step 3

3

Important
Ambient air temperature must be above 3°C (38°F).


Cover the sunload sensor.
Start the engine.
Fully open all panel outlets.
Adjust the temperature control to maximum cooling.
Select PANEL (upper) mode.
Adjust the blower speed to maximum.
Ensure that the VENT (outside air) mode indicator is not illuminated.
Does the A/C compressor operate?
--
Go to Step 4
Go to HVAC Compressor Clutch Does Not Engage

4
Place the blower motor switch in each speed position.

Does the blower motor operate correctly for each speed position?
--
Go to Step 5
Go to Blower Motor Inoperative

5
Does the blower motor provide sufficient air flow?
--
Go to Step 6
Go to Blower Motor Malfunction

6
Place the blower motor switch in the maximum speed position.
Place the mode switch in the bi-level position.
Place the outside air switch in the ON position.
Place the recirculation switch in the ON position.
Does the recirculation door operate properly?
--
Go to Step 7
Go to Air Recirculation Malfunction

7
Perform the A/C system performance test. Refer to Air Conditioning (A/C) System Performance Test in Heating, Ventilation and Air Conditioning.

Does the system pass the A/C System Performance Test?
--
Go to Step 8
Go to Air Conditioning (A/C) System Performance Test in Heating, Ventilation and Air Conditioning

8
Install a thermometer near the inside air temperature sensor.
With a scan tool, observe the Inside Temp Sensor data parameters in the Heating and Air Conditioning data list.
Does the scan tool indicate that the sensor temperatures are within 3°C (5°F) of the thermometer temperatures?
--
Go to Step 10
Go to Step 9

9
Inspect for a blocked or malfunctioning inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .

Did you find and correct the condition?
--
Go to Step 20
Go to Step 13

10
Turn the engine OFF.
Install a scan tool.
Cover the sunload sensor.
Start the engine.
Adjust driver side temperature to 22°C (72°F).
With a scan tool, observe the Sun Load Sensor data parameter in the Heating and Air Conditioning data list.
Does the scan tool indicate that the sunload sensor parameter is greater than the specified value?
4.3 V
Go to Step 11
Go to Step 15

11
Uncover the sunload sensor.
Direct a light source at the sunload sensor.
Does the voltage change?
--
Go to Step 12
Go to Step 15

12
Does the customer need to change the set temperature frequently to maintain comfort?
--
Go to Symptoms - HVAC Systems - Automatic
System OK

13
Inspect for poor connections at the harness connector of the inside air temperature sensor. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 14

14
Turn OFF the ignition.
Test the inside air temperature sensor resistance. Refer to Sensor Resistance Table .
Does the resistance measure near the specified value?
--
Go to Step 16
Go to Step 17

15
Inspect for poor connections at the harness connector of the sunload sensor. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 18

16
Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 20
Go to Step 19

17
Replace the inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .

Did you complete the replacement?
--
Go to Step 20
--

18
Replace the sunload sensor. Refer to Sun Load Sensor Replacement .

Did you complete the replacement?
--
Go to Step 20
--

19

Important
Perform the recalibration procedure for the HVAC control module.


Replace the HVAC control module. Refer to HVAC Control Module Replacement .

Did you complete the replacement?
--
Go to Step 20
--

20
Operate the system in order to verify the repair.

Did you correct the condition?
--
System OK
Go to Step 3




++++++++++++++++++++++++++++++++++

 

Thanks BestVettever!! Certainly some stuff to look at. I'm getting a bad feeling that I'm going to end up having to take her to the stealership in the end though.

Sorry for the slow response...had to go out of town to work a couple of days. Thanks again for the reply.

 

where are you working now, Bill?