Grand Cherokee 2WD Limited V8-4.7L (2002)
Fig.1 Heated Seat Switches
PASSENGER HEATED SEAT SWITCH
The heated seat switches are mounted in the instrument panel center lower bezel, which is located near the bottom of the instrument panel center
stack. The two three-position rocker-type switches, one switch for each front seat, provide a resistor multiplexed signal to the Body Control
Module (BCM) through separate hard wired circuits. Each switch has an OFF, Low, and High position so that both the driver and the front seat
passenger can select a preferred seat heating mode. Each switch has two Light-Emitting Diodes (LED), one each for the Low position and the High
position, which light to indicate that the heater for the seat that the switch controls is turned on. Each switch is also back lit by a replaceable
incandescent bulb.
The heated seat switches and their LEDs cannot be repaired. If either switch or LED is faulty or damaged, the entire switch unit must be replaced.
The incandescent switch illumination bulb and bulb holder units are available for service replacement.
There are three positions that can be selected with each of the heated seat switches: OFF, Low, or High. When the top of the switch rocker is fully
depressed, the High position is selected and the high position LED indicator illuminates. When the bottom of the switch rocker is fully depressed,
the Low position is selected and the low position LED indicator illuminates. When the switch rocker is moved to its neutral position, OFF is
selected and both LED indicators are extinguished.
Both switches provide separate resistor multiplexed hard wire inputs to the BCM to indicate the selected switch position. The BCM monitors the
switch inputs and sends heated seat switch status messages to the Heated Seat Module (HSM) or the Memory Heated Seat Module (MHSM) over
the Programmable Communications Interface (PCI) data bus. The HSM or MHSM responds to the heated seat switch status messages by
controlling the output to the seat heater elements of the selected seat. The Low heat position set point is about 36 °C (97 °F), and the High heat
position set point is about 41 °C (105 °F).
