Chrysler 300M Service Manual page 255

LH
MEMORY HEATED SEAT/MIRROR MODULE (Continued)
The most reliable, efficient, and accurate means to
diagnose the module requires the use of a DRB III
scan tool and the Service and Body Diagnostic Proce-
dures Manuals. The DRB III
vital information to the technician trying to find a
problem with the module. Diagnostic logic software is
built into the memory heated seat/mirror module to
help the person trying to locate the problem by the
most efficient means possible. Anytime a problem is
suspected, a DRB III
and used to retrieve any stored fault codes in the
memory heated seat/mirror module. If diagnostic fault
codes are present in the module, record them on a
piece of paper immediately before proceeding any fur-
ther. Then, use these fault codes to identify the prob-
lem by verifying the fault code. Example, If the module
records "DRIVER SEAT HEAT OUTPUT OPEN" fault,
locate the diagnostic procedure for this code in the
appropriate Body Diagnostic Procedures Manual and
follow the flow chart until the specific problem is
located and resolved. Once the problem is corrected,
erase the stored fault code using the DRB III
tool and verify correct heated seat system operation. If
the heated seat system appears to be functioning cor-
rectly, verify that there are no other stored codes in
the module and return the vehicle to service.
If the fault code could not be verified, such as not
finding anything wrong when following the diagnostic
flow chart in the Body Diagnostic Procedures Manual.
This is a good indication that a INTERMITTENT prob-
lem may be present. You must than attempt to find the
intermittent problem, such as moving the heating ele-
ment within the seat while testing continuity or wig-
gling the wire harness's/electrical connectors under the
seat while testing continuity. Always, eliminate all
other potential problems before attempting to replace
the memory heated seat module.
For complete circuit wiring diagrams, refer to Wir-
ing.
WARNING: REFER TO THE RESTRAINTS SECTION
OF THIS MANUAL BEFORE ATTEMPTING ANY SEAT,
STEERING WHEEL,
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRECAU-
TIONS COULD RESULT IN ACCIDENTAL AIRBAG
DEPLOYMENT AND POSSIBLE PERSONAL INJURY.
PRELIMINARY TEST
Before testing the individual components in the
heated seat system, check the following:
(1) Using the DRB III scan tool, check the mem-
ory heated seat/mirror module (MHSMM) for any
stored fault codes. Record these codes on paper for
reference and resolve using the appropriate Body
Diagnostic Procedures Manual.
scan tool can provide
scan tool should be obtained
STEERING COLUMN,
ELECTRONIC CONTROL MODULES 8E - 7
(2) Check the vehicles battery open-circuit voltage
and charging system performance. If the vehicles elec-
trical system is defective or weak it may not be suppling
sufficient energy to operate the system in question.
(3) Test each of the circuits from the heated seat
switch, elements, and sensors to the MHSMM.
Repair any shorts or open circuits as required.
REMOVAL
(1) Position the drivers seat as far upward and
rearward as possible.
(2) Open hood, disconnect and isolate the negative
battery cable remote terminal from the remote bat-
tery post.
WARNING: SOME VEHICLES ARE EQUIPPED WITH
SEATBACK
ATTEMPTING TO DIAGNOSE OR SERVICE ANY
SEAT OR POWER SEAT SYSTEM COMPONENT
YOU MUST FIRST DISCONNECT AND ISOLATE THE
BATTERY NEGATIVE CABLE. THEN WAIT TWO MIN-
UTES FOR THE SYSTEM CAPACITOR TO DIS-
scan
CHARGE BEFORE FURTHER SYSTEM SERVICE.
THIS IS THE ONLY SURE WAY TO DISABLE THE
AIRBAG SYSTEM. FAILURE TO DO SO COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
(3) Remove the two module attaching screws (Fig. 4).
OR
Fig. 4 Memory Heated Seat/Mirror Module (MHSMM)
1 - MEMORY HEATED SEAT MIRROR MODULE
2 - RECLINER MOTOR
3 - SEAT HEATER 4–WAY CONNECTOR
4 - SEAT BACK HEATER 2–WAY CONNECTOR
5 - REAR RISER MOTOR
6 - FRONT RISER MOTOR
7 - HORIZONTAL MOTOR
MOUNTED AIRBAGS.
Location
BEFORE