Chrysler 300M, Dodge Interpid. Manual - part 76
WARNING: REFER TO THE RESTRAINTS SECTION
OF THIS MANUAL BEFORE ATTEMPTING ANY
SEAT, STEERING WHEEL, STEERING COLUMN, OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
PRELIMINARY TEST
Before testing the individual components in the
heated seat system, check the following:
• Using the DRB IIIt scan tool, check the memory
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.
• Check the vehicles battery open-circuit voltage
and charging system performance. If the vehicles
electrical system is defective or weak it may not be
suppling sufficient energy to operate the heated seat
system.
• If the heated seat switch backlighting does not
light with the ignition switch in the On position,
check the fused ignition switch fuse in the junction
block and the G300 ground splice. If OK, refer to
Heated Seat Switch Diagnosis and Testing in
this section. If not OK, repair the shorted circuit or
component as required and replace the faulty fuse or
repair the open ground circuit as required.
• If the heated seat switch HI/LO LED indicators
do not light with the ignition switch in the On posi-
tion and the heated seat switch in the Low or High
position, check the fused ignition switch fuse in the
junction block. If OK, refer to Heated Seat Switch
Diagnosis and Testing in this section. If not OK,
repair the shorted circuit or component as required
and replace the faulty fuse.
• If the heated seat switch HI/LO LED indicators
light, but the heating elements do not heat, check cir-
cuit breaker #2 in the junction block. If OK, refer to
Heated Seat Element Diagnosis and Testing in
this section. If not OK, replace the faulty circuit
breaker.
DRIVER HEATED SEAT
SWITCH
DESCRIPTION
The heated seat switches are located on the out-
board seat cushion side shield of the driver and pas-
senger front seats.
The momentary, bidirectional rocker-type heated
seat switch (Fig. 1) provides a resistor-multiplexed
signal to the Memory Heated Seat/Mirror Module
(MHSMM) via a hard-wired mux circuit. Each switch
has a center neutral position and momentary Low
and High positions so that both the driver and the
front seat passenger can select a preferred level of
seat heating. Each heated seat switch contains two
Light-Emitting Diode (LED) indicator lamps, which
indicate the selected mode of the seat heater (HI/LO).
Each switch also contains a incandescent bulb, which
provides dimmer controlled back lighting of the
switch when the headlamps or park lamps are on.
The two LED indicator lamps and the incandescent
bulb in each heated seat switch cannot be repaired or
replaced. If the LED indicator lamps or back lighting
bulb are faulty or damaged, the complete heated seat
switch must be replaced.
OPERATION
The heated seat switches receive battery current
through a fused ignition switch output (run) circuit
when the ignition switch is in the On position.
Depressing the heated seat switch rocker to its
momentary High or Low position provides a hard-
wired resistance signal to the Memory Heated Seat/
Mirror Module (MHSMM). This signal tells the
module to energize the heated seat element of the
selected seat and maintain the requested tempera-
ture setting. If the heated seat switch is depressed to
a different position (LO or HI) than the currently
selected state, the module will change states to sup-
Fig. 1 Heated Seat Switch
1 - HEATED SEAT SWITCH HOUSING
2 - LIGHT EMITTING DIODE (LED) INDICATOR LAMPS
LH
HEATED SEAT SYSTEM
8G - 11
HEATED SEAT SYSTEM (Continued)