Commander 4WD V8-4.7L (2008)
Seat Heater: Description and Operation
Heated Seats - Operation
OPERATION
The heated seat system operates on battery current received through a fuse in the Integrated Power Module (IPM). The heated seat module (HSM) is fed
by a B+ circuit and continues to receive power regardless of ignition key position. The HSM monitors the ignition status message on the Controller Area
Network (CAN) data bus. If the ignition state is ON/RUN then the HSM will power the heating elements. The heated seat system will turn Off
automatically whenever the ignition switch is turned to any position except ON/RUN.
When either of the heated seat switches are depressed a resistance signal is sent to the Cab Compartment Node (CCN) or instrument cluster. The CCN
then sends a message via the CAN data bus to the heated seat module, signaling the module to energize the heating element for the selected seat. Amber
Light Emitting Diodes (LEDS) in the top portion of each switch indicate the level of heat in use: Two LEDs are illuminated for high, one for low, and
none for off. Pressing the switch once will select high-level heating. Pressing the switch a second time will select low-level heating. Pressing the switch a
third time will shut the heating elements off.
The heated seat module energizes an integral solid-state relay, which supplies battery current to the heating elements. When high-temperature heating is
selected, the heaters provide a boosted heat level during the first four minutes of operation after heating is activated. The heat output then drops to the
normal high-temperature level. If high-level heating is selected, the control system will automatically switch to the low level after two hours of
continuous operation. At that time, the number of illuminated LEDs changes from two to one, indicating the change. Operation on the low setting also
turns off automatically after two hours.
The module will automatically turn off the heating elements if it detects an OPEN or LOW short in the heating element circuit.
