A/C - Automatic Temperature Control Setting Changes
NUMBER: 24-007-01GROUP: Air Conditioning
DATE: May 18, 2001
SUBJECT:
Change In Outlet Temperature From Desired Setting
OVERVIEW:
This bulletin involves the replacement of the Automatic Zone Control assembly.
MODELS:
1999-2001 (WJ) Grand Cherokee
2001 (WG) Grand Cherokee
NOTE:
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH THE AUTOMATIC ZONE CONTROL HVAC SYSTEM AND BUILT BEFORE MARCH 08, 2001 (MDH 0308XX).
SYMPTOM/CONDITION:
A customer may experience colder or warmer than desired air temperatures coming from the vehicle HVAC system vents. This change in air temperature may occur gradually over time and only on vehicles equipped with the Automatic Zone Control (AZC) HVAC system. The air from the driver side HVAC vents will tend to increase in temperature, with this condition being more noticeable when outside ambient air temperatures are in the 16°C to 27°C (60°F to 80°F) range. The air from the front passenger HVAC vents will tend to decrease in temperature, with this condition being more noticeable when ambient temperatures are in the -7°C to 4°C (20°F to 40°F) range.
DIAGNOSIS:
Since the condition occurs gradually over time, the technician may not be able to readily verify the condition. If the HVAC system appears to be operating correctly and the customer complains of the above condition, then perform the Repair Procedure.
PARTS REQUIRED:
Qty. Part No. Description
1 55115903AE Assembly, Automatic Temperature Control
REPAIR PROCEDURE:
THIS REPAIR IS COMPATIBLE WITH DAIMLERCHRYSLER'S MOBILE SERVICE PROGRAM AND DOES NOT REQUIRE HOISTS OR OTHER FULL SERVICE FACILITY SPECIAL EQUIPMENT.
WARNING:
DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING INSTRUMENT PANEL COMPONENT SERVICE. DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE, THEN WAIT TWO MINUTES FOR THE AIRBAG SYSTEM CAPACITOR TO DISCHARGE BEFORE PERFORMING FURTHER DIAGNOSIS OR SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.
1. Disconnect and isolate the battery negative cable.
2. Remove the center bezel from the instrument panel.
3. Remove the four screws that secure the AZC assembly to the instrument panel.
4. Install the new AZC assembly, p/n 55115903AE. Install the four screws and center bezel.
5. Connect the battery negative cable to the battery.
NOTE:
IT IS IMPORTANT THAT THE FOLLOWING AZC INITIALIZATION PROCESS IS NOT INTERRUPTED. DO NOT CHANGE ANY AZC OR IGNITION SWITCH SETTINGS WHILE THE INITIALIZATION PROCESS IS OCCURRING.
6. Move the Mode selector, on the AZO assembly, to any position other than the OFF position.
7. Turn the ignition switch to the ON position.
8. Allow the AZC assembly to initialize (learn). This may take approximately one minute. During this time the technician may notice changes in fan speed and air being routed through the different HVAC vents. Once these changes have stopped the AZO initialization process is complete.
9. Turn the ignition switch to the OFF position.
NOTE:
IF THE AZC INITIALIZATION PROCESS IS INTERRUPTED, THEN A BATTERY DISCONNECT MUST BE PERFORMED PRIOR TO ATTEMPTING ANOTHER AZC INITIALIZATION.
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
Labor Operation No:
24-75-01-93 AZC, Module - Replace 0.3 Hrs
FAILURE CODE:
P8 New Part