Installation; Heated Seat Element Description; Operation; Diagnosis And Testing - Heated Seat Elements - Chrysler 300M 2002 Service Manual

LH
PASSENGER HEATED SEAT SWITCH (Continued)
Fig. 9 Negative Battery Cable Remote Terminal
1 - RIGHT STRUT TOWER
2 - AIR CLEANER INLET TUBE
3 - REMOTE TERMINAL
Fig. 10 Memory and Heated Seat Switch Location
1 - HEATED SEAT SWITCH
2 - POWER SEAT SWITCH
3 - SEAT CUSHION SIDE SHIELD
4 - MEMORY SELECTOR SWITCH

INSTALLATION

(1) Gently rock the switch back and forth in to its
mounting location.
(2) Install the appropriate seat cushion side shield.
Refer to Body for the procedure.
(3) Connect the remote negative battery cable.
HEATED SEAT ELEMENT
DESCRIPTION
The heated seat system includes four seat heating
elements two in each front seat, one for the seat
cushion and the other for the seat back. All models
use two resistor wire heating elements for each seat
that are connected in series with the Memory Heated
Seat/Mirror Module (MHSMM).
HEATED SEAT SYSTEM 8G - 13
The seat heating elements are sewn into the seat
cushion cover trim and seat back cover trim units.
The heated seat elements and the temperature sen-
sor cannot be adjusted or repaired and, if faulty or
damaged, the seat element assembly must be
replaced.

OPERATION

The heated seat elements resist the flow of electri-
cal current. When battery current is passed through
the elements, the energy lost by the resistance of the
elements to the current flow is released in the form
of heat. The temperature sensor is a NTC thermistor.
When the temperature of the seat cushion cover
rises, the resistance of the sensor decreases. The
MHSMM supplies a five-volt current to one side of
each sensor, and monitors the voltage drop through
the sensor on a return circuit. The MHSMM uses
this temperature sensor input to monitor the temper-
ature of the seat, and regulates the current flow to
the seat heating elements accordingly.
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENTS
The wire harness connectors for the seat cushion
and seat back heating elements are located under the
seat, near the rear edge of the seat cushion frame.
NOTE: WHEN CHECKING HEATED SEAT ELE-
MENTS FOR CONTINUITY, BE CERTAIN TO MOVE
THE HEATING ELEMENT BEING CHECKED. MOV-
ING THE ELEMENT, SUCH AS SITTING IN THE SEAT
WILL ELIMINATE THE POSSIBILITY OF AN INTER-
MITTENT OPEN IN THE ELEMENT WHICH WOULD
ONLY BE EVIDENT IF THE ELEMENT WAS MOVED
IN A CERTAIN DIRECTION. FAILURE TO CHECK
THE ELEMENT IN VARIOUS POSITIONS COULD
RESULT IN AN INCOMPLETE TEST.
SEAT CUSHION
(1) Unplug the 4–way heated seat cushion wire
harness connector.
(2) Check the continuity between the two heated
seat driver circuit cavities of the seat cushion cover
half of the heated seat cushion wire harness connec-
tor. If there is continuity, go to Step 3, otherwise
replace the faulty heated seat element.
(3) Check the continuity between one of the heated
seat driver circuit cavities of the seat cushion cover
half of the heated seat cushion wire harness connec-
tor and the seat cushion frame. Continuity should
NOT be present, If OK go to the Seat Back test
below, If NOT OK replace the faulty heated seat ele-
ment.