Lucerne V8-4.6L (2008)
Seat Heater: Description and Operation
Heated/Cooled Seats Description and Operation
Heated/Cooled Seats Description and Operation
The driver and front passenger climate control seat (CCS) systems each consist of the following components:
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Heated/cool seat switch
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Seat cushion heated/cool ventilation module
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Seat back heated/cool ventilation module
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Driver door module (DDM)
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Passenger door module (PDM)
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Climate control seat module (CCSM)
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HTD/COOL fuse 30-amp
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HTD/COOL/IGN3 fuse 20-amp
Air Circulation
When the heated/cool seat switch is pressed to initiate operation of the climate control seat (CCS) system, cabin air is drawn through the heated/cool
ventilation module air filter, then directed through passages in the foam of the seat cushion and seat back to the seat's occupant. In order for the CCS
system to operate to its optimum performance, it is crucial to have unrestricted air flow through the system. A dirty or restricted air filter, the blockage of
an exhaust air duct, a misaligned heated/cool ventilation module, or incorrect foam installation of the seat cushion or seat back will all have negative
effects on CCS operation.
Heated/Cool Ventilation Module
Each heated/cool seat has 2 ventilation modules, one located under the seat cushion and one located in the seat back. These modules are controlled by
the climate control seat module (CCSM). Each ventilation module contains a thermo-electric device (TED), a temperature sensor, and a blower motor.
The TED and temperature sensor are mounted downstream of the blower motor. Each TED consists of a circuit of positive and negative connections
sandwiched between 2 ceramic plates. Each ceramic plate is equipped with copper fins for heat exchange. The air flowing past these fins is either
directed as conditioned air into the seat cushion and seat back, or directed into the cabin as waste air.
A TED is essentially a solid state heat pump that is used to heat or cool the air supply to the seat cushion and seat back. When voltage is applied to a
TED, one side releases energy as heat, while the opposite side absorbs energy and gets cold. When the polarity of the current flow to the TEDs is
switched, the hot and cool sides of the TED reverse.
During the following climate control seat system description and operation, the TEDs, blower motors, and temperature sensors will be referenced
independently even though they are all packaged together as a module.
Climate Control Seat (CCS) System
The CCS system consists of two heated/cool ventilation modules and one climate control seat module (CCSM) that controls both the driver and
passenger heated/cool seats systems. The CCSM is mounted below the front passenger seat cushion. It receives power from both, battery positive voltage
and ignition 3 voltage.
Once a CCS system is activated, cabin air is drawn through the seat blower motors and directed across the fins of each of the thermo-electric device
(TED) located under the seat cushion and in the seat back. The air is either heated or cooled as it passes over the TEDs. This conditioned air is then
directed through channels in the foam of the seat pad and through small holes in the seat cover to the occupant. Once the system is activated, the CCSM
uses a set of algorithms to control the temperature of the selected heating or cooling modes.
Climate Control Seat Module (CCSM) Power and Ground
Battery positive voltage is supplied at all times to the climate control seat module (CCSM) through the battery positive voltage circuit and the 30-amp
HTD/COOL fuse that is located in the rear fuse block. This voltage is used by the CCSM to supply power to the thermo-electric devices (TEDs) and the
blower motors. Battery positive is also supplied to the CCSM through the ignition 3 voltage circuit and the 20-amp HTD/COOL/IGN3 fuse also located
in the rear fuse block. The ignition 3 voltage is used to power up the CCSM and allows the climate control seat (CCS) system to operate only with the
ignition in the ON position. The CCSM is grounded through the module ground circuit and G300.
Keyword 2000 Serial Data
The keyword protocols utilize a single wire bi-directional data line between the module and the scan tool. The message structure is a request and
response arrangement. The keyword serial data line is used for scan tool diagnostics of the climate control seat module (CCSM) only. Other modules on
the vehicle do not exchange data on this circuit.
Modes of Operation
