Air Conditioning

[Chatham52]

My air conditioner blows colder air out the passenger side than the driver's side. The driver's side is not cold at all. I have a dual control in my car. It is a 2000 Pontiac Grand Prix, 3.8 litre. Anyone else experience this? What do I do to fix it?

[BNaylor]

How cold is the passenger side output? Did you put a temperature gauge to it? On the manual single and the dual zone HVAC systems poor cooling felt at the driver's side can be caused by a low refrigerant charge so check the charge at the low side service port and compare to specs based on humidity and temperature. Another issue would be good charge but a temperature vent actuator not working properly. There are two. One for the driver's side and one for passenger. Controlled via the climate control unit when you adjust temperature.

[brcidd]

You have the typical symptoms of a system which has lost more than half of its refrigerant, due to a leak- (evap cools passenger side first, then driver's side) so the procedure is to recover and weigh the refigerant (to confirm system loss of charge)- the find and fix leak, then vacuum and recharge to system spec-- most likely source of leak is the compressor shaft seal on your V-5 compressor- If you can't do this work- then employ a place that can...

You can also verify lack of cooling/loss of charge by adding refrigerant- but use a gage set with both high and low side gages to be safe- but remember- if you have a leak- it is still there and needs to be fixed to do it right....

[rkvons]

I am compelled to comment here. I have a 98 GTP with the automatic dual-zone temperature control system. A few years after I got the car (brand new, by the way) I had the situation where the temperatures were different between driver side and passenger side. The passenger side was cold, the drivers side was hot. So I went in and removed the drivers side temperature door actuator. Which, by the way, is extremely difficult to get out because of its location. I went to the dealer to inquire about another one and they wanted $175 for it. I then dissassembled the one I removed and found that it contains a little motor which has a gear on it that drives another gear and eventually turns the actuator. One particular gear that was pressed onto a spline had cracked. This crack would interfere with the gear that was driving it from the motor. What I did was press off the cracked gear and rotate it to an orientation that would place the cracked area out of the range of use, since the gear did not rotate a full 360 degress anyway. I reassembled this and put it back in, but found that there was no change. What I had to do, was discconnect the battery and then reconnect it. I could be wrong, but it seems like when I did this, the computer put the two actuators through an initialization sequence that was done apparently to determine the position of the actuators. After that, they seemed to change based on the temperature control knob. Less than two weeks ago I had a similar situation and disconnected the battery and reconnected it and it cleared up the skew between where the computer thinks the actuators are and where they really are. Remember that you will LOC your radio when you disconnect the battery.

[BNaylor]

Originally Posted by rkvons

I am compelled to comment here. I have a 98 GTP with the automatic dual-zone temperature control system. A few years after I got the car (brand new, by the way) I had the situation where the temperatures were different between driver side and passenger side. The passenger side was cold, the drivers side was hot. So I went in and removed the drivers side temperature door actuator. Which, by the way, is extremely difficult to get out because of its location. I went to the dealer to inquire about another one and they wanted $175 for it. I then dissassembled the one I removed and found that it contains a little motor which has a gear on it that drives another gear and eventually turns the actuator. One particular gear that was pressed onto a spline had cracked. This crack would interfere with the gear that was driving it from the motor. What I did was press off the cracked gear and rotate it to an orientation that would place the cracked area out of the range of use, since the gear did not rotate a full 360 degress anyway. I reassembled this and put it back in, but found that there was no change. What I had to do, was discconnect the battery and then reconnect it. I could be wrong, but it seems like when I did this, the computer put the two actuators through an initialization sequence that was done apparently to determine the position of the actuators. After that, they seemed to change based on the temperature control knob. Less than two weeks ago I had a similar situation and disconnected the battery and reconnected it and it cleared up the skew between where the computer thinks the actuators are and where they really are. Remember that you will LOC your radio when you disconnect the battery.

Possibly a good suggestion however I don't see where this is a automatic climate control (ACC) system in the OP's first post so your suggestion may not be applicable unless the OP confirms he/she has a CJ2 ACC system. On the CJ2 systems there is a programmer glitch where the temperature actuators get out of alignment for some unexplained reason. Normally this occurs when there is a battery fault or the ACC is not manually turned off first before disconnecting the battery. Disconnecting the battery usually helps on the CJ2 systems but not on the manual dual zone systems. The CJ2 systems were eventually trashed by GM on later year Grand Prix models and no longer installed from the factory.

If the OP has the CJ2 ACC then it won't hurt to try this suggestion. Also, the CJ2 ACC system has on-board diagnostics which actually checks the actuators/servos.

On-Board Diagnosis Mode
The CJ2 air conditioning is equipped with an on-board diagnostic feature which allows the heater-A/C control to detect certain system faults. The diagnostic feature may also be used to display certain data parameters. If the heater-A/C control detects a fault in the system, the man symbol will flash during the first 2 minutes of vehicle operation.

Entry into the diagnostic mode is gained by pressing in on both temperature knobs at the same time for 5 seconds. The following display modes are found within diagnostics:

The diagnostic pointer
The diagnostic value
By rotating the driver temperature knob one detent in either direction, the display is toggled between pointer and value. The value displayed is the decimal equivalent of the RAM contents. A 2 is formed using the minus sign and the leading 1 in order to display values over 199.

A diagnostic pointer mode is identified by a minus sign preceding the pointer number. The pointer provides an index, which identifies the corresponding diagnostic value. The diagnostic trouble codes (DTCs) reside under diagnostic pointer -00. The pointer will be set to this position upon initial entry into diagnostics. If more than one code exists, the codes will be displayed sequentially at a rate of 2 seconds per fault. Rotating the passenger temperature knob will switch the diagnostic pointers. A wrap around feature is provided if the pointer is continued past either end. Other data used by the computer resides under different diagnostic pointers, and may not be of use in observing the system. Press any mode button in order to exit the diagnostic mode.


Important
A 2-digit trouble code indicates the fault is current. A 3-digit trouble code indicates a history fault.


Clearing Codes
Press the A/C mode button in order to clear codes from the heater-A/C control.

Any of the following components may cause malfunction in the temperature controls:

The refrigerant system
The electrical wiring connections
The vacuum connections
Faulty components that have mechanical problems, such as sticking valves
As a part of the diagnostic process inspect the following components:

The refrigerant, vacuum or mechanical systems. Refer to Vacuum Test .
The blower controls. Refer to 66-0 .
The compressor controls. Refer to Cell 67: RPO L36, L67 .
The air delivery controls. Refer to Power and Grounds .
The temperature controls. Refer to Electrical Diagnosis. Complete the diagnostic procedure for the heater A/C control microprocessor.


Make sure to turn the climate control off first, then hit both buttons at the exact same time. I know one time it took it like 5 seconds, the next time it took like 15.Then rotate the left knob until the desired number appears.

Position Description
-00 Error codes Click here for the Trouble Codes chart

-01 (servo position) 103-107 43-162
-02 (servo position) 128 120-202
-03 (servo position) 150 162-194
-04 CJ2 Fan Speed Low=15, 29, 44, 58, 71, 86, 110=High, CJ2 Unit will adjust to other increments as needed
-05 (servo position) 93 88-191
-06 (servo position) -152 00-252
-07 (servo position) 00 0, 34-255
-08 (servo position) -155 00-255
-09 (servo position) 00 0, 23-255
-10 ? 04 04
-11 CJ2 Vent Mode 1=Def, 2=Bilevel, 3=Auto, 4=Lower, 5=Def+Lower
-12 Engine Coolant Temp -60 degrees 80=104, 95=131, 100=140 Peak@135°F
-13 Actual Vehicle Speed in MPH
-14 (servo position) 00 21=0
-15 ? 39 44
-16 Radiator low fan turn on temp -106 207
-17 Radiator low fan turn off temp 196 199
-18 ? 50 51
-19 (servo position) 162-169 40-172
-20 Affected by cabin temp sensor 89 50-172
-21 (servo position) 00 ?
-22 Sunload Sensor -117 LIGHT=126, 218=DARK
To return to normal operation, press the MODE button next to the Passenger temperature knob.


This is a list of the Trouble Codes displayed by the CJ2 Unit.
A two digit code indicates a current fault while a three digit code indicates a historic fault.
Trouble Code Description
00 No System Fault
01 or 101 Inside Air Temperature Sensor Short
02 or 102 Inside Air Temperature Sensor Open
03 or 103 Ambient Outside Temperature Sensor Short
04 or 104 Ambient Outside Temerature Sensor Open
05 or 105 LH Electric Actuator Open or Short
06 or 106 RH Electric Actuator Open or Short
07 or 107 UART Serial Data Line Fault
08 or 108 Solar Sensor Open