Lucerne V8-4.6L (2008)
the module to bring the ventilation module fin temperature up to the pre-determined Temperature Set Point of the Max Heat Mode. The module
does this by setting the blower motor speed control to a pre-determined voltage while ramping up the ventilation module voltage from 0 volts to
the maximum voltage, not to exceed 5 seconds, at which point the system transitions to Max Heat Mode. The Heat SoftStart Mode will only be
attempted once per ignition cycle.
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Max Heat Mode-Upon completion of the Heat SoftStart Mode, the CCSM will initiate Max Heat Mode. The intent of the MAX Heat Mode is to
maintain the fin temperature to the pre-determined Temperature Set Point in order for the CCSM to go into the Control Heat Mode. The CCSM
does this by maintaining the TED at the maximum voltage while maintaining the minimum required airflow across the fins. After max heat
duration has been reached, or upon achieving the pre-determined Temperature Set Point, the system transitions to the Control Heat Mode.
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Control Heat Mode-At the completion of Max Heat Mode, the CCSM will initiate Control Heat Mode. The intent of the Control Heat Mode is to
maintain the desired fin temperature or the set point temperature. The CCSM does this in two ways; first by adjusting the voltage supply to the
blower motor to control blower motor speed, then secondly by controlling the voltage supplied to the TED. The CCSM updates these voltages
once every second. Increasing the blower motor speed will decrease the fin temperature. If the maximum blower motor speed is achieved and the
fin temperature is still above the set point of high heat, the CCSM will then begin to control the TED voltage to achieve Temperature Set Point.
Decreasing the TED voltage decreases the fin temperature. If the CCSM is trying to raise the fin temperature to set point by using TED voltage,
and the fin temperature cannot be raised because the TED voltage is at the maximum, the CCSM reduces the blower motor speed to achieve the
Temperature Set Point.
Cooled Seat Operation
When the cool seat switch is pressed for High Cool, the climate control seat module (CCSM) will transition to the COOL state. In response to this
command, the CCSM applies a pre-determined voltage through the ventilation module cool control circuits to the cool side of the thermo-electric devices
(TEDs) while providing a ground through the ventilation module heat control circuits to the heat side of the TEDs. A pre-determined voltage is also
applied to the blower motors. The CCSM uses the following sequence, beginning with the Cool SoftStart Mode, to achieve the set point temperature
before it can enter the Open Loop Cool Mode.
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Cool SoftStart Mode-The intent of the Cool SoftStart Mode is for the CCSM to bring the TED fin temperature to maximum cool temperate. The
CCSM does this by setting the blower motor speed control voltage to 0 volts, while ramping up the TED voltage duty cycle from 0 volts to
maximum voltage duty cycle over a period not to exceed 5 seconds. Then, with the TEDs at maximum voltage, the CCSM will increase the blower
speed to maximum voltage, and keep these settings for the MAX COOL DURATION. After which the system transitions to the Open Loop Cool
Mode.
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Open Loop Cool Mode-At the completion of Cool SoftStart Mode, the CCSM will initiate Open Loop Cool Mode. The intent of this mode is to
maintain the set point fin temperature based on the input of the cool seat switch. First, by controlling the speed of the blower motor, then secondly,
by controlling TED voltage. The CCSM updates these voltages once every second.
Fault State
The climate control seat system will operate normally in the battery voltage range of 9-16 volts. If the system voltage falls outside of this voltage range,
the module will shut down all outputs until the system returns to its normal operating voltage range. The system will also transition to the fault state per
the conditions listed below, by shutting down all outputs for the seat in which the fault occurred.
High Temperature Fault State
During the heating or cooling modes, if the TED temperatures listed below are exceeded for more than 4 seconds, the system will enter the High
Temperature Fault State. At which time the CCSM will set the TED voltage duty cycle to 0%, set the blower speed control to maximum voltage to blow
ambient air over the TEDs, attempting to reduce the TED temperature below the listed maximums. The system will operate in this mode for 30 seconds.
If the over temperature fault still exists after 30 seconds, the system will transition to the FAULT state for the remainder of the ignition cycle. If the over
temperature fault clears, the system will then transition to the appropriate heat or cool softstart mode. The following temperatures are based upon
individual readings of either sensor:
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Heat mode TED temperature exceeds 230°F (110°C).
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Cool mode TED temperature exceeds 149°F (65°C).
Temperature Delta Fault
During the heating or cooling modes, if the climate control seat module (CCSM) detects a temperature difference between the seat cushion and seat back
TED temperature sensors exceeding the delta temperature listed below for more than 4 seconds, the system will enter the Temperature Delta Fault state.
At which time the CCSM will set the TED voltage duty cycle to 0%, set the blower speed control to maximum voltage to blow ambient air over the
TEDs, attempting to reduce the delta temperature to less than 68°F. The system will operate in this mode for 30 seconds. If the delta temperature fault
still exists after 30 seconds, the system will transition to the FAULT state and remain there until the ignition has been set to OFF.
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Delta between the seat cushion and seat back temperature sensors is 104°F (40°C).
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This fault state is disabled in the back only mode.
