Lucerne V6-3.9L (2009)
There are 3 modes available for climate control seat (CCS) system operation, heated seat, cool seat, and back only heat operation. When a heat or cool
seat mode signal request is received, the climate control seat module (CCSM) will activate both the seat cushion and seat back ventilation modules.
When the seat BACK ONLY mode button is pressed once, the CCSM will deactivate the seat cushion ventilation module and leave the seat back
ventilation module ON. Press the BACK ONLY mode button a second time and the CCSM will re-activate the seat cushion ventilation module.
Heated/Cooled Seat Switch and Door Module
The driver and front passenger seats are controlled by a separate heated/cool seat switch. Ground is supplied to the heated/cool seat switch through the
low reference circuit and the respective door module. The door module plays an important part of the climate control seat (CCS) operation, first by
relaying the selected switch inputs to the CCSM, and second, by controlling the mode and temperature indicators of the heated/cool seat switch.
The following describes the sequence of operation of the heated/cool seat switch, and how the door module responds to each of the switch inputs.
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High Temperature-When either the heat or cool seat switch is pressed once, ground is applied through the switch contacts and the switch signal
circuit to the door module. In response to this signal, the door module then sends a message via GMLAN serial data to the memory seat module
(MSM). In response to this message, the MSM then sends a pulse width modulation (PWM) signal through the heated/cool seat mode signal
circuit to the CCSM indicating the switch input. The door module then applies a ground through the appropriate heat or cool seat indicator control
circuit to the switch, illuminating the selected heat or cool mode indicator. At the same time, the module also applies a ground through the high,
medium, and low temperature indicator control circuits of the switch illuminating all 3 temperature indicators, indicating the high temperature
mode.
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Medium Temperature-When the switch is pressed a second time, the door module signals the MSM, the MSM then relays the message to the
CCSM of the medium temperature request. The door module then removes the ground from the high temperature indicator, leaving the medium
and low temperature indicators illuminated, indicating the medium temperature mode.
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Low Temperature-When the switch is pressed a third time, the door module signals the MSM, the MSM then relays the message to the CCSM of
the low temperature request. The door module then removes the ground from the medium temperature indicator, leaving the low temperature
indicator illuminated, indicating the low temperature mode.
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System Off State-After the switch is pressed a fourth time, the door module signals the MSM, the MSM then relays the message to the CCSM of
the system OFF request. The door module then removes the grounds from indicator control circuits turning OFF the appropriate heat or cool mode
indicator and the low temperature indicator.
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Seat Back Only Heat Mode-The back only mode will operate only in the heat mode in any one of the above mentioned temperature settings. When
the back only switch is pressed once, the door module signals the MSM, the MSM then relays the message to the CCSM of the back only mode
request. The door module then supplies a ground through the seat back only mode indicator control circuit to the switch, illuminating the BACK
ONLY mode indicator.
Temperature Sensors
As mentioned above in the heated/cool ventilation module description, the seat cushion and seat back temperature sensors are each packaged with a
thermo-electric device (TED) and blower motor as an assembly. The seat temperature sensors are thermistors which are attached directly to the fins of
each TED. The climate control seat module (CCSM) supplies a 5-volt reference voltage through the temperature sensor signal circuit and ground through
the temperature sensor low reference circuit to the respective seat cushion and seat back temperature sensors. As the temperature of the TED changes,
the resistance of the thermistor varies changing the feedback voltage of the temperature sensor signal circuit. This voltage varies from 0.5-4 volts. The
CCSM monitors this voltage signal to determine the fin temperature so that it can adjust and maintain the seat temperature to the selected switch input.
Blower Motors
Also, as mentioned above in the heated/cool ventilation module description, the seat cushion and seat back blower motors are each packaged with a
thermo-electric device (TED) and temperature sensor as an assembly. Each blower motor contains logic that will allow for the blower to operate only
when the ignition is in the ON position. When the ignition is ON and the climate control seat module (CCSM) is powered up, the module supplies battery
positive voltage through the blower supply voltage circuit to the logic of the blower motors. When the heated/cool seat switch is pressed, the CCSM
applies a pre-determined voltage through the blower speed control circuits to the blower motors. The module also supplies each blower motor with a
ground path through the blower low reference circuits.
With the climate control seat (CCS) system, the speed of the blower motor is not related directly to the High, Med, or Low input from the heated/cool
seat switch. The speed of the blower motor is related directly to TED temperature as described below in heated and cooled seat operation.
Heated Seat Operation
When the heated seat switch is pressed for High Heat, the climate control seat module (CCSM) will transition to the HEAT state. In the heat state, the
CCSM applies a pre-determined voltage through the ventilation module heat control circuits to the heat side of the thermo-electric devices (TEDs), while
providing a ground through the ventilation module cool control circuit to the cool side of the TEDs. A pre-determined voltage is also applied to the
blower motors. The CCSM uses the following sequence beginning with the Heat SoftStart Mode to achieve the set point temperature before it can enter
the Control Heat Mode. If the seat temperature is already above the Temperature Set Point, the CCSM will skip the Heat SoftStart Mode and proceed to
the Control Heat Mode.
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Heat SoftStart Mode-While in transition to the heat mode, the CCSM will initiate the SoftStart Mode. The intent of the Heat SoftStart Mode is for
