OPERATION
There are two momentary positions that can be
selected with each of the heated seat switches, Low
and High. When the switch closest to the driver/pas-
senger is depressed, the Low position is selected and
the “LO” position LED indicator illuminates. When
the switch farthest from the driver/passenger is
depressed, the High position is selected and the “HI”
position LED indicator illuminates. If the switch is
depressed a second time in the same direction, Off is
selected and both LED indicators are extinguished.
Both heated seat switch assemblies provide sepa-
rate resistive multiplexed inputs to the appropriate
door module. The Door Module then sends a PCI
Data Bus message to the Memory Heated Seat
Adjustable Pedal Module (MHSAPM) to indicate the
selected switch position. The module responds to the
heated seat switch messages by controlling the 12v
output to the front seat heating elements. The Low
heat position set point is about 35° C (97° F), and the
High heat position set point is about 40° C (105° F).
DIAGNOSIS AND TESTING - DRIVER HEATED
SEAT SWITCH
For complete circuit diagrams, refer to Wiring.
CHECKING SWITCH SIGNAL AND WIRING AT THE
DOOR MODULE
(1) Disconnect and isolate the battery negative
cable.
(2) Access and disconnect the connector from the
driver door module. Visually inspect wiring terminals
for damage that would prevent positive connection. If
not OK, repair or replace the necessary components.
(3) Reconnect the negative battery cable and the
driver door module. Turn heated seat ON in the LO
position. Using an Ohmmeter, check the resistance
between the driver heated seat switch mux circuit
and fused ignition switch output circuit. Resistance
should be about 8 kiloohms (8020 ohms ±4%). If not
OK, check resistance directly at switch. If OK, go to
Step 4. If NOT OK replace the switch or faulty wir-
ing.
(4) Turn heated seat ON in the HI position. Using
an Ohmmeter, check the resistance between the
driver heated seat switch mux circuit and fused igni-
tion switch output circuit. Resistance should be about
2.4 kiloohms (2400 ohms ±4%). If not OK, check
resistance directly at switch. If OK, go to Step 5. If
NOT OK replace the switch or faulty wiring.
(5) With the system ON in the HI position, Check
for proper battery voltage and ground at the appro-
priate cavities. If OK, test heated seat element. If
NOT OK, repair open or wiring short.
CHECKING SWITCH ONLY
(1) The heated seat switch assembly used on CS
vehicles includes other switches. (Refer to 8 - ELEC-
TRICAL/POWER SEATS/DRIVER SEAT SWITCH -
DIAGNOSIS AND TESTING)
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the front door trim panel. Refer to
Front Door Trim Panel Removal in the Body section
for the procedure.
(3) Disconnect the harness from the door module.
(4) Remove the heated seat switch assembly by
pressing in the four clips.
INSTALLATION
(1) Install the heated seat switch assembly.
(2) Connect the harness to the door module.
(3) Install the front door trim panel. Refer to the
Body section for the procedure.
(4) Reconnect the battery negative cable.
HEATED SEAT ELEMENTS
DESCRIPTION
The heated seat system utilizes two heated seat
elements in each seat, one for the seat cushion (Fig.
2) and the other for the seat back. Although two dif-
ferent heated seat systems are used for the front and
2nd row rear seats, the heated seat elements func-
tion the same way. The two elements for each 2nd
row rear seat are connected in series with the 2nd
row Heated Seat Module (HSM). The two elements
for each front seat are connected in parallel with the
Memory
Heated
Seat Adjustable
Pedal
Module
(MHSAPM). One temperature sensor is used for each
rear seat only, and it is located in the rear seat cush-
ion heated seat element. The front heated seat sys-
tem does not utilize a temperature sensor the heated
seat elements. The heated seat temperature sensor is
a Negative Temperature Coefficient (NTC) ther-
mistor. (Refer to 8 - ELECTRICAL/HEATED SEATS/
HEATED SEAT SENSOR - DESCRIPTION) for more
information on the rear heated seat sensor.
The heated seat elements are glued onto the seat
cushion and seat back cushion foam. The heated seat
elements and the temperature sensor cannot be
adjusted or repaired and, if faulty or damaged, the
heated seat element assembly must be replaced.
Refer to the procedure later in this section.
CS
HEATED SEAT SYSTEM
8G - 11
FRONT HEATED SEAT SWITCH (Continued)