Grand Cherokee 2WD V6-3.7L (2008)
Control Assembly: Customer Interest
A/C - Disproportionate Temp. Change When Knob Adjusted
NUMBER: 24-002-09 REV. A
GROUP: Heating & Air Conditioning
DATE: November 12, 2009
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 24-002-09, DATED MAY 6, 2009. ALL REVISIONS ARE HIGHLIGHTED
WITH **ASTERISKS** AND INCLUDE A NEW PART NUMBER FOR THE ATC CONTROL HEAD IN CELSIUS.
THE wiTECH DIAGNOSTIC APPLICATION IS THE PREFERRED METHOD FOR FLASHING ECUs.
HELP USING THE wiTECH DIAGNOSTIC APPLICATION FOR FLASHING AN ECU IS AVAILABLE BY SELECTING "HELP" THEN "HELP
CONTENTS" AT THE TOP OF THE wiTECH DIAGNOSTIC APPLICATION WINDOW.
THE wiTECH SOFTWARE LEVEL MUST BE AT RELEASE 10.01 OR HIGHER TO PERFORM THIS PROCEDURE.
THE StarSCAN(R) FLASH FILES FOR THIS BULLETIN MUST BE RETRIEVED FROM THE INTERNET.
StarMOBILE DESKTOP CLIENT, STAR MOBILE or StarSCAN MAY ALSO BE USED TO PERFORM THIS PROCEDURE.
SUBJECT:
FLASH - Too Large Of A Temperature Increase When The Temp Knob Is Moved One Or Two Detents from Full Cold Position
OVERVIEW:
This bulletin involves replacing the manual temperature control head on MTC equipped vehicles. **ATC equipped vehicles will require either a flash or
ATC control replacement depending on software version. **
MODELS:
2007 - 2008
(WH)
Grand Cherokee (International Markets)
2007 - 2008
(WK)
Grand Cherokee
2007 - 2008
(W2)
Grand Cherokee CKD
2007 - 2008
(XK)
Commander
2007 - 2008
(XH)
Commander (International Markets)
NOTE:
The MTC portion of this bulletin applies to vehicles built between July 2, 2006 (MDH 0702XX) and January 14, 2008. (MDH 0114XX) equipped
with a manual temperature control system (Sales Code HAA).
SYMPTOM/CONDITION:
Customer may complain that panel temperatures increase too rapidly when the temp knob is moved one or two detents from full cold while in manual
mode. This service bulletin will provide the customer with smaller, more expected, panel temperature increases per detent move from the full cold
temperature knob position.
DIAGNOSIS:
1. Once the vehicle is at operating temperature, place controls to panel mode, adjust temperature to full cold and turn NC on. Turn the blower to High
and with the use of a thermometer, measure and record the outlet temperature from the center ducts. This temperature acts as a base point to measure
the change in the temperatures between the next few detents. Move the temperature knob one detent towards the hot region (clockwise), wait for the
system to stabilize and take another measurement. Repeat this procedure for the next two detentes. Compare the temperature differences between
each detent if they are greater then 10 °F (5.5 °C) proceed to Step 2. If the temperature differences are less the 10 °F (5.5 °C) then this bulletin does
not apply. The system is operating as it was designed.
2. **Is the vehicle equipped with ATC?
a. Yes > proceed to ATC REPAIR PROCEDURE:
b. No > proceed to MTC REPAIR PROCEDURE:**
