Mechanics

NO HEAT ON ONE SIDE

1999 Jeep Grand Cherokee • V8 4WD Automatic • 155,000 miles

I have a 1999 Jeep Grand Cherokee with a dual zone climate control unit. On the passenger side, the unit only blows cold air. The drivers side will blow hot air. What could be the problem and how much should it cost to repair?
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Nirgal2002
December 13, 2010.



The heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.

Wrenchtech
Dec 13, 2010.
What would be the range in cost for repair/replacement?

Tiny
Nirgal2002
Dec 13, 2010.
First you have to find out what the problem is and what has to be done to fix it.

Wrenchtech
Dec 13, 2010.
CJ MEDEVAC,

What if you see only a code 0 when you do that check?

Tiny
Nirgal2002
Dec 16, 2010.
Weeeeeeeeeeeell,

I kinda saw you were sorta lost on what was going on with your heat/ air

I reckon if you aren't sorta mechanical minded, this would be like me running a computer efficiently. NOT!

I had came across this LINK, while trying to aid a friend with his Rig (same as yours)

His did not come up with the codes in the link either

HIS PROBLEM WAS A THERMOSTAT--HE LIVES IN ARKANSAS.I AM IN SOUTH CAROLINA. So I did not have "HANDS ON"

I am not a mechanic (paid type) Imma Jeep CJ kinda feller! I answer Confidently in the "5" & "7" Forums

Ain't many CJs to fix---They seldom break!

So I thought I could maybe "Throw you a bone, While I waited on one of 'em to come in!"

I usually can find the answer I need, by really looking for resources, others might not try. Or know about

I do not know much about your rig, mostly generic things common with other 4X4s. BUT STILL, I AM GOOD WITH RESOURCES THAT MAY. OR. MAY NOT HELP!

OK, theres one out of the way. Here's the other.

Wrenchtech! DO YOU HAVE ANY BETTER THOUGHTS THAN I?

YOU ARE THE "ASE CERTIFIED GUY"---I am merely a "SELF CERTIFIED REAR LAWN AUTOMOTIVE (REAL JEEP) TECHNICIAN". CAN YOU PLEASE, CRAWL INTO THIS THIS VEHICLE, AND MAYBE LOOK A LITTLE CLOSER AT POSSIBILITIES?

THANKS FELLER!

Nirgal2002, PLEASE WAIT IN OUR LUXURIOUS WAITING AREA, OUR BEST MECHANIC (Wrenchtech) WILL BE WITH YOU SOON!

The Medic

Tiny
CJ MEDEVAC
Dec 16, 2010.


The Automatic Zone Control (AZC) control module has a system self-diagnostic mode which continuously monitors various parameters during normal system operation. If a system fault is detected, a current and historical fault is recorded. When the current fault is cleared, the historical fault remains until reset (manually or automatically). Both the current and historical fault codes can be accessed through either the front panel, or over the Programmable Communications Interface (PCI) bus using a DRB III scan tool, and the proper Diagnostic Procedures.

The AZC control module is capable of three different types of self-diagnostic tests, as follows:

* Fault Code Tests
* Input Circuit Tests
* Output Circuit/Actuator Tests

The information that follows describes:

* How to read the self-diagnostic display
* How to enter the AZC control module self-diagnostic test mode
* How to select the self-diagnostic test types
* How to perform the different tests

Entering the AZC Self-Diagnostic Mode
To enter the AZC self-diagnostic mode, perform the following:

1. Depress the A/C and Recirc buttons at the same time and hold. Rotate the left temperature control **** clockwise (CW) one detent.
2. If you continue to hold the A/C and Recirc buttons depressed, the AZC control module will perform a Segment Test of the vacuum fluorescent (VF) display In the Segment Test you should see all of the display segments illuminate as long as both buttons are held. If a display segment fails to illuminate, the vacuum fluorescent display is faulty and the heater-A/C control must be replaced.
3. After viewing the Segment Test, release the A/C and Recirc buttons and the display will clear momentarily If the display remains blank then no faults are set in the system. Should there be any faults, either "current" or "historical", all fault codes will be displayed in ascending numerical sequence (note no effort is made to display fault codes in chronological order). Each fault code is displayed for one second before the next code is displayed. Once all fault codes have been displayed, the system will then repeat the fault code numbers. This will continue until the left side set temperature control is moved at least one detent position in the CW direction or the ignition is turned "OFF".

For further diagnosis, refer to Body Control Module (BCM). See: Powertrain Management\Computers and Control Systems\Testing and Inspection\Diagnostic Trouble Code Descriptions\Detailed Descriptions\Heating and A/C

Fault Code Tests
Fault codes are two-digit numbers that identify a circuit that is malfunctioning. There are two different kinds of fault codes.

1. Current Fault Codes - Current means the fault is present right now. There are two types of current faults: input faults, and system faults. If the system has a current fault when the ignition is turned "ON", or during normal operation a current fault occurs, the right side set temperature digits will display "ER" at maximum intensity while the left side set temperature digits are blanked.
2. Historical Fault Codes - Historical or stored means that the fault occurred previously, but is not present right now. A majority of historical fault codes are caused by intermittent wire harness or wire harness connector problems.

NOTE: A battery disconnect will erase all faults stored in Random Access Memory (RAM) of the AZC control module. It is recommended that all faults be recorded before they are erased.

Retrieving Fault Codes

1. To begin the fault code tests, depress the A/C and Recirc buttons at the same time and rotate the left temperature control **** clockwise (CW) one detent, then release the push-button.

http://i602.photobucket.com/albums/tt106/Desi501/78613910.gif

http://i602.photobucket.com/albums/tt106/Desi501/78613911.gif

Wrenchtech
Dec 16, 2010.