WARNING: The front passenger seat assembly contains critical components that affect the front passenger
airbag deployment. Correctly functioning front passenger seat components are critical for the Occupant
Classification System (OCS) to properly classify the front passenger and calculate the proper airbag deploy-
ment. Unapproved modifications or service procedures to the front passenger seat assembly, its related
components, or trim cover may inadvertently change the airbag deployment in case of a frontal crash. This
could result in death or serious injury to the front seat passenger if the vehicle is involved in an accident.
The following requirements must be strictly adhered to:

•

Do not modify the front passenger seat assembly or components in any way.

•

Do not modify the front seat center console or center position seat in any way.

•

Do not use prior or future model year seat trim covers not designated for the specific model being
repaired. Always use the correct seat trim cover specified for the vehicle.

•

Do not replace the seat trim cover with an aftermarket trim cover.

•

Do not add a secondary trim cover other than those approved by DaimlerChrysler/Mopar.

•

At no time should any Supplemental Restraint System (SRS) component or SRS related component or
fastener be modified or replaced with any part except those which are approved by DaimlerChrysler/Mo-
par.

Vehicles with the heated seat option can be visually identified by the two heated seat switches located in the center
stack of the instrument panel. The heated seat system allows the driver and front seat passenger to select from two
different levels of electrical seat heating (HI/LO). The heated seat system for this vehicle includes the following
major components, which are described in further detail later in this section:

•

Heated Seat Switches - Two heated seat switches are used per vehicle. One switch is used for each front
seat. The switches are mounted in the instrument panel, below the radio. Each switch also includes two Light-
Emitting Diode (LED) indicator lamps and an incandescent back lighting bulb.

•

Heated Seat Module - This module contains the solid state electronic control and diagnostic logic circuitry for
the heated seat system. One heated seat module is used per vehicle and is mounted under the drivers front
seat cushion. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/MEMORY HEATED SEAT/MIR-
ROR MODULE - DESCRIPTION) for additional heated seat module information.

DR/DH

HEATED SEATS - SERVICE INFORMATION

8G - 17

•

Heated Seat Elements - Four heated seat elements are used per vehicle. One element is used for each front
seat back and one element and sensor assembly is used for each front seat cushion. The heating elements
are integral to the individual front seat and seat back cushions and cannot be removed once installed at the
factory. Replacement seat heating elements are available, without having to replace the entire seat cushion or
trim cover. (Refer to 8 - ELECTRICAL/HEATED SEATS/HEATED SEAT ELEMENT - REMOVAL) for the
detailed procedure.

•

Heated Seat Sensors - Two heated seat sensors are used per vehicle. One heated seat temperature sensor
is used for each front seat cushion. The sensors are integral to the individual front seat cushion heating ele-
ments and cannot be removed once installed at the factory. Replacement seat heating elements with the sen-
sors are available, without having to replace the entire seat cushion or trim cover. (Refer to 8 - ELECTRICAL/
HEATED SEATS/HEATED SEAT ELEMENT - REMOVAL) for the detailed procedure.

OPERATION

The heated seat module receives fused battery current through the Integrated Power Module. The heated seat
switches receive battery current from the Cab Compartment Node (CCN) only when the ignition switch is in the On
position and the engine is running. The heated seat module shares a common ground circuit with each of the
heated seat elements. The heated seat system will control the surface temperature of the seat cushion to within the
designed temperature set points of the system.

The heated seat system will also automatically turn off whenever the ignition switch is turned to any position except
On, or if the engine quits running. If the ignition switch is turned to the Off position or if the engine quits running
while a heated seat is ON, the heated seat will remain Off after the engine is restarted until a heated seat switch is
depressed again. This helps prevent the vehicles battery from being drained by the heated seat system.

The heated seat module monitors inputs from the heated seat sensors and the heated seat switches. In response
to these inputs the heated seat module uses its internal programming to control 12v to the heated seat elements in
both front seats and to control the heated seat LED indicator lamps located in both of the heated seat switches. The
heated seat module is also programmed to provide self-diagnostics, if a problem with the heated seat system is
detected. If the module detects certain failures within the heated seat system, it will provide a visual indication of the
failure by flashing the indicator lamps in the appropriate heated seat switch. The heated seat module will automat-
ically turn off the heated seat elements if it detects a short or open in the heated seat element circuit or a heated
seat sensor value that is out of range.

DIAGNOSIS AND TESTING

HEATED SEAT SYSTEM

HEATED SEAT SYSTEM SELF-DIAGNOSIS

The heated seat system is capable of performing some self-diagnostics. The following table depicts the various
monitored conditions which will be reported to the vehicle operator or technician by flashing the individual heated
seat switch Light Emitting Diode (LED) indicator lamps. Refer to the HEATED SEAT SYSTEM SELF-DIAGNOSIS
table for condition identification. The driver heated seat switch indicator lamps will flash if a malfunction occurs in
the driver heated seat, and the passenger heated seat switch indicator lamps will flash for a passenger heated seat
malfunction. If a monitored heated seat system malfunction occurs, the switch indicator lamps will flash at a pulse
rate of about one-half second on, followed by about one-half second off for a duration of about one minute after the
switch for the inoperative heated seat is depressed in either the Low or High direction. This process will repeat
every time the inoperative heated seat switch is actuated until the problem has been corrected.

8G - 18

HEATED SEATS - SERVICE INFORMATION

DR/DH

HEATED SEAT SYSTEM SELF-DIAGNOSIS

Monitored

condition

Switch High

Indicator Lamp

Switch Low

Indicator Lamp

Heated Seat

Element Shorted

Flashing

Heated Seat

Element Open

Flashing

Off

Heated Seat

Sensor Value Out

of Range

Off

Flashing

Diagnostic logic is built into the heated seat module to help locate the problem by the most efficient means possible.
Anytime a problem is suspected, locate the diagnosis and testing procedure for the component in question and
follow the steps until the specific problem is located and resolved. Once the problem is thought to be corrected,
verify correct system operation. If the heated seat system is functioning correctly return the vehicle to service.

If a problem could not be verified such as not finding anything wrong when following the diagnostic procedure, this
is a good indication that an INTERMITTENT problem may be present. You must then attempt to find the intermittent
problem, such as moving the heating element within the seat while testing continuity or wiggling the wire harness’s/
electrical connectors under the seat while testing continuity. Always, eliminate all other potential problems before
attempting to replace the heated seat module.

PRELIMINARY TEST

Refer to Wiring for the location of complete heated seat system wiring diagrams. Before testing the individual com-
ponents in the heated seat system, perform the following preliminary checks:

WARNING: DISABLE THE AIRBAG SYSTEM BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. DISCONNECT AND ISOLATE
THE BATTERY NEGATIVE 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 ACCI-
DENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

•

If the heated seat switch back lighting and the cluster illumination lamps do not illuminate with the headlamps
or park lamps turned On, refer to the Instrument Cluster section of the service manual for the location of
cluster illumination lamp diagnosis and testing procedures. If the heated seat switch back lighting does not
illuminate, but the cluster illumination lamps do illuminate with the headlamps or park lamps turned On, (Refer
to 8 - ELECTRICAL/HEATED SEATS/DRIVER HEATED SEAT SWITCH - DIAGNOSIS AND TESTING) for the
heated seat switch diagnosis and testing procedures.

•

If a single LED indicator lamp for one heated seat switch does not operate and the heated seat elements do
heat, (Refer to 8 - ELECTRICAL/HEATED SEATS/DRIVER HEATED SEAT SWITCH - DIAGNOSIS AND
TESTING) for the heated seat switch diagnosis and testing procedures.

•

If both LED indicator lamps for a heated seat switch operate, but the heated seat elements do not heat, (Refer
to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/MEMORY HEATED SEAT/MIRROR MODULE -
DIAGNOSIS AND TESTING) for heated seat module diagnosis and testing procedures.

•

If the indicator lamp on either heated seat switch remains illuminated after the heated seat has been turned
Off, (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/MEMORY HEATED SEAT/MIRROR
MODULE - DIAGNOSIS AND TESTING) for heated seat module diagnosis and testing procedures.

DR/DH

HEATED SEATS - SERVICE INFORMATION

8G - 19

Content .. 339 340 341 342 ..