AZC fault codes
01 = IR thermister circuit open
02 = IR thermister circuit shorted
03 = Fan pot shorted
04 = Fan pot open
05 = Mode pot shorted
06 = Mode pot open
07 = IR sensor delta too large
08 = Reserved
09 = Reserved
10 = One of four motor drivers has drive "A" shorted to ground
11 = Engine air intake temperature bus message missing
12 = Country code bus message missing
13 = Mode motor not responding
14 = AI (Recirc) motor not responding
15 = Left temperature door not responding
16 = Right temperature door not responding
17 = Mode door travel range too small
18 = Mode door travel range too large
19 = AI (Recirc) door travel too small
20 = AI (Recirc) door travel too large
21 = Left temperature door travel too small
22 = Left temperature door travel too large
23 = Right temperature door travel too small
24 = Right temperature door travel too large
25 = Calibration check sum error
26 = Engine coolant temp bus message missing
27 = Vehicle speed bus message missing
28 = Engine RPM bus message missing
29 = OAT bus message missing
30 = Display intensity bus message missing
31 = VIN number bus message missing
32 = Raw OAT buss message missing
33 = IR thermister circuit was open
34 = IR thermister circuit was shorted
35 = Fan pot was shorted
36 = Fan pot was open
37 = Mode pot was shorted
38 = Mode pot was open
39 = IR sensor delta was too large
40 = Reserved
41 = Reserved
42 = One of four motor drivers had drive 9A9 shorted to ground
43 = Engine air intake temperature bus message missing
44 = Country code buss message missing
45 = Mode motor was not responding
46 = AI (Recirc) motor was not responding
47 = Left temperature door was not responding
48 = Right temperature door was not responding
49 = Mode door travel range too small
50 = Mode door travel range too large
51 = AI (Recirc) door travel range too small
52 = AI (Recirc) door travel range too large
53 = Left temperature door travel too small
54 = Left temperature door travel too large
55 = Right temperature door travel too small
56 = Right temperature door travel too large
57 = Calibration check sum error
58 = Engine coolant temp bus message missing
59 = Vehicle speed bus message missing
60 = Engine RPM bus message missing
61 = OAT bus message missing
62 = Display intensity bus message missing
63 = VIN number bus message missing
64 = Raw OAT bus message was missing
65 = Reserved
66 = Reserved
67 = Reserved
WJ climate controls
WJ climate systems
1999-2004 Grand Cherokee models feature either a Manual Temperature Control (MTC) or Automatic Zone
Control (AZC). The Automatic control is available only on Limited or Overland models. The manual
temperature control HVAC system uses a combination of electrical, and vacuum controls. The Automatic
Zone Control HVAC system uses only electrical controls. These controls provide the vehicle operator with a
number of setting options to help control the climate and comfort within the vehicle. Refer to the owner’s
manual in the vehicle glove box for more information on the suggested operation and use of these controls.
Both a/c heater control panels are located on the instrument panel inboard of the steering column and below
the radio. Both control panels contain rotary-type temperature control knob(s), a rotary type mode control
switch knob, a rotary-type blower motor speed switch knob and an air conditioning compressor push button
switch. The rear window defogger push button switch is also located on a/c heater control panel. The AZC
control panel also features a recirculation push button switch and a vacuum fluorescent display area.
The AZC control module uses infrared sensing technology to control occupant comfort levels, not the actual
passenger compartment air temperature. Dual infrared sensors mounted in the face of the control unit
independently measure the surface temperature to maintain customer-perceived comfort temperature under
changing conditions. Dual Zone temperature control provides wide side-to-side variation in comfort
temperature to exceed the needs of either front seat occupant. This sensing system replaces interior air
temperature and solar sensors used to approximate direct sensing control through complex control programs.
The AZC system:
Communicates over the Programmable Communication Interface Multiplex System (PCI) Bus.
Has dual infrared sensors, mounted in the AZC module face, which independently measure surface
temperature to maintain occupant comfort levels.
Has dual-zone temperature-controls to provide a wide side-to-side variation in temperature to meet the
needs of either front seat occupant.
Can be operated in a manual mode.
Uses engine temperature data, received over the PCI Bus, for cold engine blower lock-out.
Uses engine RPM data, received over the PCI Bus, for wide-open throttle A/C cut-out.
Uses vehicle speed data, received over the PCI Bus, to determine air-flow over the condenser for optimum
Uses Ambient Temperature Sensor data, received over the PCI Bus, to optimize comfort control.
Provides an A/C request to the BCM when compressor operation is desired.
Provides a request to the BCM when rear defogger operation is desired.
Controls fan speed, providing 10 blower speeds in manual mode and infinite speeds in automatic mode.
The Blower Motor Controller provides a 5.0 volt signal to the AZC Module over the Blower Motor Control
circuit. The AZC Module provides a variable duty cycle ground to the 5.0 volt signal based on input from the
blower switch. When the blower switch is set to LO speed, the AZC Module provides a short duty cycle (less
time grounding the signal voltage). As higher blower speeds are requested, the AZC Module increases the
duty cycle (more time grounding the signal voltage). When the blower switch reaches HI speed, the duty
cycle increases to where the signal pattern is almost a flat line (with brief voltage spikes).
Controls electronic door actuator operation.
A simplified control system for operation of the mode, recirculation, and temperature control actuators
provides positive positioning without the complexity of feedback from position sensors. The AZC Module
knows the number of operating actuator revolutions required for full door travel as well as the number of
actuator commutator pulses per revolution. Using these parameters, the AZC Module runs the actuator for
the number of commutator pulses that correspond to the desired door position. To maintain accuracy, the
system recalibrates itself periodically at known zero and full travel conditions.
AZC system doors:
Two, two-wire electronic blend door actuators.
One, two-wire electronic mode door actuator.
One, two-wire electronic recirculation door actuator.
The 2003-2004 model year AZC Module is NOT interchangeable with 1999-2002 AZC Modules due to
revised control software.
AZC fault codes
Fault codes are two-digit numbers that identify a circuit that is malfunctioning. 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 DRBIII scan tool, and the appropriate diagnostic information.
The two different kinds of fault codes are:
1. Current Fault Codes - Current means the fault is present right now. There are two types of current faults:
input faults, and system faults.
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
AZC self-diagnostic mode:
1. To enter the self-diagnostic mode, depress the a/c and recirc buttons at the same time and hold. Rotate
the left temperature control knob clockwise (CW) one detent.
2. If you continue to keep 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 a/c heater control must be replaced.
3. After viewing the Segment Test, release the A/C and Recirc buttons and the display will clear momentarily.
If there are no fault codes, the “00” display value will remain in the VF window. Should there be any codes,
each will be displayed for one second in ascending numerical sequence (note: no effort is made to display
faults in the order they occurred). The left side set temperature display will be blanked and the right side set
temperature display will indicate current and historical codes (8 historical max) presently active.
Once all codes have been displayed, the system will repeat the fault code numbers. This will continue until
the left side set temperature control is moved at least one detent position in either direction, by pressing
both the A/C and Recirc buttons at the same time, or the ignition is turned off. Record all of the fault codes,
then see the Current and Historical Fault Code charts below for the descriptions.
Clearing fault codes
Current faults cannot be electronically cleared. Repair must be made to the system to eliminate the fault
causing code. Historical fault codes can be cleared manually, or automatically. To clear a historical fault
manually, depress and hold either the A/C or Recirc button for at least three seconds while the display is in
the fault code mode of operation. Historical fault codes are cleared automatically when the corresponding
current fault code has been cleared, and has remained cleared for 72 ignition cycles. The faults have been
cleared when two horizontal bars appear in the Test Selector display.
Calibrating AZC door actuators
Calibrate the door actuators after making any repairs to the AZC system. To calibrate the door actuators
proceed as follows:
1. Turn the ignition on.
2. Set the AZC to automatic.
3. Turn the ignition off.
4. Remove the IOD fuse from the Power Distribution Center. Wait several seconds, and then install the IOD
5. Turn the ignition on. Do not touch any of the AZC controls for at least one minute to allow the calibration
function to run to completion.
Every 20 key cycles the AZC head initiates a re-calibration routine which identifies pulse counts required to
achieve full door travel. Also during this routine all modes and functions are validated as functional. When
the self calibration routine is complete, the control head resets itself to its last settings.
The air conditioning compressor will engage in certain modes to cool and remove moisture from air entering
the passenger compartment. The AZC control, when it is not set in the auto mode, always defaults to A/C
enabled. The LED illuminates when the control requests A/C. The customer must toggle A/C off by
depressing the button every time he turns to manual mode or the A/C is enabled. Additionally, when the
vehicle is off for a "calibratable" amount of time, automatic A/C is again enabled and the customer must
again force it off by depressing the button.
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as of January 1, 2011. We will continue to bring
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|Dual Zone System repair kit
Single Zone System repair kit
The JeepHeater single zone repair kit includes a solid
aluminum axle design which can be used for both single zone
Laredo and dual zone Limited style Grand Cherokee. Both
blend doors move together at all times.
Plastic housing not included. Your Jeep already has one.
The JeepHeater dual zone repair kit includes a two piece
aluminum axle design which can be used only for dual zone
Limited style Grand Cherokee. Both blend doors move
independantly from one another at all times.
Plastic housing not included. Your Jeep already has one.
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