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Dual Climate Zone Problems

12-07-2009, 02:19 PM
I have a 98 GP GT. It has the dual climate controls for driver and passenger. The driver side blows out cold regardless of temp setting. The passenger side responds as it should, Where do I need to start? Is there a door or something that is stuck, not allowing warm coolant to the driver side heater core, are there 2 separate heater cores? Any suggestions would be greatly appreciated.:banghead:

12-08-2009, 07:21 AM
Welcome to AF.

No, one heater core only and it is constant flow meaning coolant is flowing through it at all times.

Is this the manual or digital (ACC) climate control system? If you have the digital you can run a diagnostics. In the dual zone systems there are two temperature actuators that control the heater/AC doors in the HVAC assembly. One for passenger side and other for drivers.

12-08-2009, 12:06 PM
I'm not sure the difference between digital and manual, I think it is digital as you set the temp to lets say 72 degrees, and it is supposed to maintain the temp. How do you run a diagnostics test on the system? If there is an actuator that is sticking where would I find it? Thanks again.

12-08-2009, 06:04 PM
I had this issue. For me, it turned out to be the actuator. You can open up your glovebox and look to the upper left and see the one for the passenger side. At least this will give you an idea of what you are dealing with. When you change the temperature setting, you'll see the shaft turning on it. The one for the drivers side is a little bit harder to get to. It can be accessed from the drivers side underneath. I removed mine and took it apart to find that a gear inside was cracked. One thing you might want to try before all that is to remove the fuse that powers your controls for a minute. Then stick it back in. It seems to go through an initialization that may correct it. Of course, I would also listen to what B.Nayler has to say.

12-08-2009, 07:14 PM
Good info rkvons and thanks for sharing it.

It sounds like the OP has the CJ2 digital ACC. Here is the CJ2 diagnostics. Some people had good luck running it and others found it not helpful, of course depending on the type HVAC problem. Also, check to see if the maintenance man icon on the climate control unit is on or blinking.

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.

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@135F
-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

12-09-2009, 01:05 AM
Thanks for the replys, the info will help and give me a great place to start. Thanks again, I will try to post if any of these suggestions are my problem.

12-10-2009, 06:47 PM
Did you recently replace the battery?

12-11-2009, 02:56 AM
The battery was replaced approximately 6 months ago, why do you ask?:banghead:

12-11-2009, 01:37 PM
I may be wrong but it is worth a shot. If you have a digital dual climate control system, it may just need to be calibrated. The problem that you described is common after there is a power loss to the system like changing a battery.

The way to calibrate the system is to turn it off and have key off and pull the fuse to the radio. Wait 5 minutes, put fuse back, turn key on for 30 seconds but don't start engine, turn climate control on, and start your car to see what happens.

I may be a little off on the sequence so if other want to add to it, go ahead.

Hope that helps.

12-12-2009, 01:15 PM
Thanks,will try and let you know

12-13-2009, 09:40 PM
Well, spent the last several hours trying the different things everyone has suggested. The diagnostics check did not show any faults, and the other suggestion was not the problem,pulled the radio fuse and tried to reset, as the battery was replaced several months ago, but no luck. I do know that the freon in the system is low, as this summer there was no cool air blowing when a/c was selected. But this should have no effect on the heating, only the conditioning of the air. I still must have an actuator problem,or whatever controls the warm air flow to the drivers side. Where the heck is this control and what does it look like? This is very drustrating and any suggestions woul be great.:banghead:

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