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Seat Heating System and Seat Cooling System Cadillac CTS II

Seats 11 illustrations ~4435 words

Fastener Tightening Specifications

ApplicationSpecification
MetricEnglish
Front Seat Cushion Ventilation Heating and Cooling Blower Screw3 N.m27 lb in

Scheme 94

Scheme 94: Heated/Cooled Seat Schematics
Scheme 94: Heated/Cooled Seat Schematics

Scheme 95

Scheme 95
Scheme 95

Scheme 96

Scheme 96
Scheme 96

Scheme 97

Scheme 97
Scheme 97

DIAGNOSTIC CODE INDEX

DTCDescription
DTC B1925 or B2170B1925 02: Left Seat Heater Sensor Circuit Short to Ground B1925 05: Left Seat Heater Sensor Circuit Short to Battery or Open B2170 02: Right Seat Heater Cushion Sensor Circuit Short to Ground B2170 05: Right Seat Heater Cushion Sensor Circuit Short to Battery or Open
DTC B2345B2345 4B: Front Seat Heater Current Sensing Calibration Out of Range B2345 13: Front Seat Heater Temperature Above Threshold B2345 42: Front Seat Heater Current Sensing Calibration Not Present
DTC B2425 or B2430B2425 0D: Left Seat Heater Cushion Circuit Resistance Above Threshold B2425 0E: Left Seat Heater Cushion Circuit Resistance Below Threshold B2430 0D: Right Seat Heater Cushion Circuit Resistance Above Threshold B2430 0E: Right Seat Heater Cushion Circuit Resistance Below Threshold
DTC B2508 or B2509B2508 01: Seat Heater Relay Circuit Short to Battery B2508 02: Seat Heater Relay Circuit Short to Ground

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Memory Seat Module B+ Terminal 5 X31, 2, B2425 0D, B2430 0D1, 2, B2425 0D, B2430 0D
Driver Heated Seat Element Supply VoltageB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Element ControlB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Temperature Sensor SignalB1925 02B1925 05B1925 05B2345 13, B2345 42, B2345 4B
Driver Heated Seat Temperature Sensor Low ReferenceB1925 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Element Supply VoltageB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Element ControlB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Temperature Sensor SignalB2170 02B2170 05B2170 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Temperature Sensor Low ReferenceB2170 05B2345 13, B2345 42, B2345 4B
1. Power seats inoperative 2. Heated seats inoperative

Circuit/System Description

The heated seat temperature sensor that set this diagnostic trouble code (DTC) is located in the seat cushion just under the seat cover with the seat heating element. The memory seat module (MSM) supplies a 5 V reference voltage through the temperature sensor signal circuit and a ground through the low reference circuit to the sensor. The module monitors the voltage of the sensor signal circuit to determine the temperature of the seat. The temperature sensor varies in resistance based on the temperature of the heating element causing the signal voltage to change. Once the seat reaches the set temperature, the module will then cycle the control circuit of the heating elements ON and OFF in order to maintain the desired seat temperature based on the feedback voltage from the sensor.

Conditions for Running the DTC

The MSM must be powered.

B1925 02, B2170 02

The temperature sensor voltage drops below 0.8 V for more than 1 second.

B1925 02, B2170 05

The temperature sensor voltage is greater than 5 V for more than 1 second.

Action Taken When the DTC Sets

The heated seat function for the affected seat will be disabled.

Conditions for Clearing the DTC

  1. The current DTC will clear and set the code to history 3 seconds after the reference voltage returns to normal operating range and the ignition is cycled OFF then back to ACC or RUN.
  2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

B1925 02 or B1925 05

  1. Ignition OFF, disconnect the X2, X5 harness connectors at the MSM.
  2. Test for 1.4 k-300 kohms between the signal circuit terminal 1 X5 and the low reference circuit terminal 3 X2. If less than the specified range, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat temperature sensor. If greater than the specified range, test the signal circuit and low reference circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the seat temperature sensor.
  3. Ignition OFF, connect the X2, X5 harness connectors at the MSM.
  4. Disconnect the harness connector at the seat cushion heating element/temperature sensor.
  5. Ignition ON, test for 4.8 - 5.2 V between the signal circuit terminal C and ground. If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the MSM. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.
  6. If all circuits test normal, replace the MSM.

B2170 02 or B2170 05

  1. Ignition OFF, disconnect the X2, X5 harness connectors at the MSM.
  2. Test for 1.4k - 300 kohms between the signal circuit terminal 2 X5 and the low reference circuit terminal 6 X2. If less than the specified range, test for a short between the signal and low reference circuits. If the circuits test normal, replace the seat temperature sensor. If greater than the specified range, test the signal circuit and low reference circuit for a short to voltage or an open/high resistance. If the circuits test normal, replace the seat temperature sensor.
  3. Ignition OFF, connect the X2, X5 harness connectors at the MSM.
  4. Disconnect the harness connector at the seat cushion heating element/temperature sensor.
  5. Ignition ON, test for 4.8 - 5.2 V between the signal circuit terminal C and ground. If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the MSM. If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.
  6. If all circuits test normal, replace the MSM.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Driver or Passenger Seat Back Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  2. «Driver Seat Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  3. «Passenger Seat Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  4. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Memory Seat Module B+ Terminal 5 X31, B2425 0D, B2430 0D1, B2425 0D, B2430 0D
Driver Heated Seat Element Supply VoltageB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Element ControlB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Temperature Sensor SignalB1925 02B1925 05B1925 05B2345 13, B2345 42, B2345 4B
Driver Heated Seat Temperature Sensor Low ReferenceB1925 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Element Supply VoltageB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Element ControlB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Temperature Sensor SignalB2170 02B2170 05B2170 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Temperature Sensor Low ReferenceB2170 05B2345 13, B2345 42, B2345 4B
1. Power seats inoperative

The heated seat heating elements are controlled by a common high current relay internal to the memory seat module (MSM) and by individual low side element control circuits. The MSM connects the heater element supply voltage circuits for both seats to a common reference point. This reference point is biased to approximately 2.5 V. Before the MSM will allow heated seat operation, it checks to see if the heating element supply voltage circuits and control circuits are shorted to ground or voltage. Once the module verifies that it is not closing into a shorted heating element, it allows heated seat operation. After which it continues to monitor for a shorted a circuit.

The MSM must be powered.

B2345 13

Any temperature sensor input that remains below 1.5 V for more that 1 second.

B2345 42

This DTC will set if the module calibration is not present.

B2345 4B

This DTC will set if the module calibration is out of range.

The heated seat function for both seats will be disabled.

  1. The current DTC will clear and set the code to history 3 seconds after the reference voltage returns to normal operating range and the ignition is cycled OFF then back to ACC or RUN.
  2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X2, X5 harness connector at the MSM.
  2. Test for greater than 1.4 kohms between the signal and low reference circuits listed below: Driver seat cushion terminal 1 X5 and terminal 3 X2 Passenger seat cushion terminal 2 X5 and terminal 6 X2. If less than the specified value, test for a short between the signal and low reference circuits. If the circuits test normal, replace the appropriate temperature sensor.
  3. If all circuits test normal, replace the MSM.

B2345 42 or B2345 4B

If either DTC is set, replace the MSM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Driver or Passenger Seat Back Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  2. «Driver Seat Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  3. «Passenger Seat Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  4. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Memory Seat Module B+ Terminal 5 X31, B2425 0D, B2430 0D1, B2425 0D, B2430 0D
Driver Heated Seat Element Supply VoltageB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Element ControlB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Temperature Sensor SignalB1925 02B1925 05B1925 05B2345 13, B2345 42, B2345 4B
Driver Heated Seat Temperature Sensor Low ReferenceB1925 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Element Supply VoltageB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Element ControlB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Temperature Sensor SignalB2170 02B2170 05B2170 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Temperature Sensor Low ReferenceB2170 05B2345 13, B2345 42, B2345 4B
1. Power seats inoperative

The driver and front passenger heated seats are controlled by the memory seat module (MSM) that is located under the driver seat cushion. When the heated seat is active, the module applies power through a common voltage supply circuit to the seat heater elements. The module controls the seat temperature by providing a pulse width modulation (PWM) ground through the seat heater element control circuit to the heater elements. The module then monitors the current flow through the heating elements and the rate of change of the temperature sensor to verify correct heated seat operation.

The MSM must be powered and the heated seat must be enabled.

B2425 0D, B2430 0D

By measuring current and voltage output to the seat heating elements every 10 seconds, the MSM calculates that the heating element resistance is above the maximum resistance.

B2425 0E, B2430 0E

By measuring current and voltage output to the seat heating elements every 10 seconds, the MSM calculates that the heating element resistance is below the minimum resistance.

The heated seat function for the affected seat will be disabled.

  1. The current DTC clears when the malfunction is no longer present, and the power mode changes to OFF then back to ACC or RUN.
  2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

B2425 0D or B2425 0E

  1. Ignition OFF, disconnect the X3 harness connector at the MSM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X3 harness connector at the MSM and disconnect the harness connector at the seat back heating element.
  4. Test for 1.7 - 7.0 ohms between the control circuit terminal A and control circuit terminal B. If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the seat back heating element. If greater than the specified range, replace the seat back heating element.
  5. Connect the harness connector at the seat back heating element and disconnect the X1 harness connector at the MSM.
  6. Test for 1.7 - 7.0 ohms between the control circuit terminal 6 and control circuit terminal 11. If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the seat cushion heating element. If greater than the specified range, test the control circuits for an open/high resistance. If the circuits test normal, replace the seat cushion heating element.
  7. If all circuits test normal, replace the MSM.

B2430 0D or B2430 0E

  1. Ignition OFF, disconnect the X3 harness connector at the MSM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X3 harness connector at the MSM and disconnect the harness connector at the seat back heating element.
  4. Test for 1.7 - 7.0 ohms between the control circuit terminal A and control circuit terminal B. If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the seat back heating element. If greater than the specified range, replace the seat back heating element.
  5. Connect the harness connector at the seat back heating element and disconnect the X1, X4 harness connectors at the MSM.
  6. Test for 1.7 - 7.0 ohms between the control circuit terminal 14 X1 and the control circuit terminal 14 X4. If less than the specified range, test for a short between the control circuits. If the circuits test normal, replace the seat cushion heating element. If greater than the specified range, test the control circuits for an open/high resistance. If the circuits test normal, replace the seat cushion heating element.
  7. If all circuits test normal, replace the MSM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Driver or Passenger Seat Back Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  2. «Driver Seat Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  3. «Passenger Seat Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  4. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Memory Seat Module B+ Terminal 5 X31, B2425 0D, B2430 0D1, B2425 0D, B2430 0D
Driver Heated Seat Element Supply VoltageB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Element ControlB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Temperature Sensor SignalB1925 02B1925 05B1925 05B2345 13, B2345 42, B2345 4B
Driver Heated Seat Temperature Sensor Low ReferenceB1925 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Element Supply VoltageB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Element ControlB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Temperature Sensor SignalB2170 02B2170 05B2170 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Temperature Sensor Low ReferenceB2170 05B2345 13, B2345 42, B2345 4B
1. Power seats inoperative

The driver and passenger seat heating elements are controlled by a common high current relay internal to the memory seat module (MSM) and by individual low side element control circuits. The MSM connects the heated seat heater element supply voltage circuits for both seats to a common reference point. This reference point is biased to approximately 2.5 V. Before the MSM will allow heated seat operation, it checks to see if this reference voltage is shorted to ground or voltage. Once the module verifies that it is not closing to a shorted heating element, it allows for heated seat operation. The module will then continue to monitor the heating elements for a shorted circuit.

The MSM must be powered.

B2508 01

The MSM detects a short to voltage on the heater element supply voltage circuit or control circuit.

B2508 02

The MSM detects a short to ground on the heater element supply voltage circuit or control circuit.

The heated seat function for both the driver and passenger seats will be disabled.

  1. The current DTC will clear and set a history code 3 seconds after the reference voltage returns to normal operating range and the ignition is cycled OFF then back to ACC or RUN.
  2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

  1. Ignition OFF, disconnect the X1, X4 harness connectors at the MSM.
  2. Test for infinite resistance between the control circuit terminal 6 X1 and ground. If not the specified value, test the control circuits for a short to ground.
  3. Test for infinite resistance between the control circuit terminal 14 X1 and ground. If not the specified value, test the control circuits for a short to ground.
  4. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 6 X1 and ground. If the test lamp illuminates, test the control circuits for a short to voltage.
  5. Verify that a test lamp does not illuminate between the control circuit terminal 14 X1 and ground. If the test lamp illuminates, test the control circuits for a short to voltage.
  6. If all circuits test normal, replace the MSM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Driver or Passenger Seat Back Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  2. «Driver Seat Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  3. «Passenger Seat Cushion Heater Replacement (KA1)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  4. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, setup, and programming

Symptoms - Seat Heating and Cooling

IMPORTANTThe following steps must be completed before using the symptom tables.
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data link.
  2. Refer to «Heated/Vented Seat Description and Operation»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system) in order to familiarize yourself with the system functions.

Visual/Physical Inspection

  1. Inspect for aftermarket devices which could affect the operation of the power seats. Refer to «Checking Aftermarket Accessories»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__checking-aftermarket-accessories) .
  2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
  3. Inspect the seat adjuster track for conditions which may cause binding or objects within the seat adjustment range which obstruct movement or interfere with wiring.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

  1. «Heated Seat Inoperative»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  2. «Vented Seat Malfunction»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
B+ MSM Terminal 5 X31, 2, B2425 0D, B2430 0D1, 2, B2425 0D, B2430 0D
Driver Heated Seat Element Supply VoltageB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Element ControlB2508 02B2425 0DB2508 01B2425 0E
Driver Heated Seat Temperature Sensor SignalB1925 02B1925 05B1925 05B2345 13, B2345 42, B2345 4B
Driver Heated Seat Temperature Sensor Low ReferenceB1925 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Element Supply VoltageB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Element ControlB2508 02B2430 0DB2508 01B2430 0E
Passenger Heated Seat Temperature Sensor SignalB2170 02B2170 05B2170 05B2345 13, B2345 42, B2345 4B
Passenger Heated Seat Temperature Sensor Low ReferenceB2170 05B2345 13, B2345 42, B2345 4B
1. Power seats inoperative 2. Heated seats inoperative

The driver and passenger heated seats are controlled by separate heated seat switches located in the radio/HVAC control panel. When a heated seat switch is pressed, a serial data message is sent to the radio. The radio then serves as a gateway to transmit the serial data message to the memory seat module (MSM) indicating the heated seat command. In response to this signal, the MSM then applies or removes battery voltage through the element supply voltage circuit of the seat heating elements. The MSM then sends a serial data message back to the radio to gateway the information to the radio/HVAC control panel to either illuminate or turn off the appropriate temperature indicator.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

  1. Ignition OFF, disconnect the X3 harness connector at the MSM.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Ignition OFF, connect the X3 harness connector at the MSM.
  4. Ignition ON, observe the scan tool Radio Driver Heated Seat Sw. parameter while pressing the driver HEATED seat switch. The readings should change between Inactive and Active. If not the specified value, replace the radio/HVAC control panel.
  5. Observe the scan tool Radio Pass. Heated Seat Sw. parameter while pressing the passenger HEATED seat switch. The readings should change between Inactive and Active. If not the specified value, replace the radio/HVAC control panel.
  6. If the scan tool readings are normal, there are no DTCs set, and the driver and/or passenger heated seat is inoperative, replace the MSM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Radio Control Assembly Replacement (with Navigation Display)»(/cadillac/cts/ii-2007-2014/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system) or «Radio Control Assembly Replacement (without Navigation Display)»(/cadillac/cts/ii-2007-2014/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system)
  2. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, setup, and programming
  1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures) prior to using this diagnostic procedure.
  2. Review «Strategy Based Diagnosis»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__strategy-based-diagnosis) for an overview of the diagnostic approach.
  3. «Diagnostic Procedure Instructions»(/cadillac/cts/ii-2007-2014/remont/oem-general-information/#vehicle-diagnostic-information-diagnostic-information-and-procedures__diagnostic-procedure-instructions) provides an overview of each diagnostic category.
CircuitShort to GroundOpen/High ResistanceShort to VoltageSignal Performance
Ignition Voltage1, 41, 4
Driver Seat Back Ventilation Heating and Cooling Module Ignition Voltage1, 42
Driver Seat Cushion Ventilation Heating and Cooling Module Ignition Voltage1, 43
Driver Vented Seat Signal111
Driver Seat Back Ventilation Heating and Cooling Module Ground2
Driver Seat Cushion Ventilation Heating and Cooling Module Ground3
Passenger Seat Back Ventilation Heating and Cooling Module Ignition Voltage1, 45
Passenger Seat Cushion Ventilation Heating and Cooling Module Ignition Voltage1, 46
Passenger Vented Seat Signal444
Passenger Seat Back Ventilation Heating and Cooling Module Ground5
Passenger Seat Cushion Ventilation Heating and Cooling Module Ground6
1. Driver Vented Seat is Inoperative 2. Driver Vented Seat Back is Inoperative 3. Driver Vented Seat Cushion is Inoperative 4. Passenger Vented Seat is Inoperative 5. Passenger Vented Seat Back is Inoperative 6. Passenger Vented Seat Cushion is Inoperative

The driver and passenger vented seats are controlled by separate vented seat switches located in the radio/HVAC control panel. Ignition voltage is supplied to the driver and passenger seat ventilation heating and cooling modules through the MISC IGN fuse located in the underhood fuse block. Ground for the driver seat ventilation heating and cooling modules is provided at G200, while ground for the passenger seat ventilation heating and cooling modules is provided at G201. When a vented seat switch is pressed a serial data message is sent to the radio, the radio then serves as a gateway to transmit the serial data message to the memory seat module (MSM) indicating the vented seat command. In response to this message, the MSM applies a low side pulse width modulation (PWM) signal through the control circuits to the seat cushion and seat back ventilation heating and cooling modules indicating the vented seat command. The logic in the modules set the blower speed to the switch set point. Both seat ventilation heating and cooling module blower motors run drawing cabin air around and away from occupant. The MSM then sends a serial data message back to the radio to gateway the information back to the radio/HVAC control panel to either illuminate or turn off the appropriate switch indicator.

Schematic Reference

Connector End View Reference

Description and Operation

Electrical Information Reference

  1. «Circuit Testing»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__circuit-testing)
  2. «Connector Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__connector-repairs)
  3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__testing-for-intermittent-conditions-and-poor)
  4. «Wiring Repairs»(/cadillac/cts/ii-2007-2014/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-diagnostic-information-and-procedures__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, observe the scan tool Radio Driver Cooled Seat Button parameter while pressing the driver VENTED seat switch. The reading should change between Inactive and Active. If not the specified value, replace the radio/HVAC control panel.
  2. Observe the scan tool Radio Passenger Cooled Seat Button parameter while pressing the passenger VENTED seat switch. The reading should change between Inactive and Active. If not the specified value, replace the radio/HVAC control panel.
  3. If all scan tool readings test normal and the driver and/or passenger vented seat is inoperative, refer to Circuit/System Testing.
  1. Ignition OFF, disconnect the harness connector at the appropriate seat ventilation heating and cooling module.
  2. Test for less than 5 ohms between the ground circuit terminal B and ground. If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  4. Connect a test lamp between the signal circuit terminal A and battery voltage.
  5. Press the VENTED seat switch through the high, medium, and low positions to OFF. The test lamp should illuminate until the OFF position is reached. If the test lamp does not illuminate, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the MSM. If the test lamp is ON with the switch in the OFF position, test the signal circuit for a short to ground. If the circuit tests normal, replace the MSM.
  6. If all circuits test normal, test or replace the seat ventilation heating and cooling module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

  1. «Driver or Passenger Seat Back Ventilation Heating and Cooling Blower Replacement (KB6)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system) or «Driver or Passenger Seat Back Ventilation Heating and Cooling Blower Replacement (W2E)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  2. «Driver or Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement (KB6)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system) or «Driver or Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement (W2E)»(/cadillac/cts/ii-2007-2014/remont/seats/#seat-heating-system-and-seat-cooling-system)
  3. «Radio Control Assembly Replacement (with Navigation Display)»(/cadillac/cts/ii-2007-2014/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system) or «Radio Control Assembly Replacement (without Navigation Display)»(/cadillac/cts/ii-2007-2014/remont/entertainment-systems/#cellular-system-entertainment-system-and-navigation-system)
  4. «Control Module References»(/cadillac/cts/ii-2007-2014/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, setup, and programming

Scheme 98

Scheme 98: Driver or Passenger Seat Back Cushion Heater Replacement (KA1)
Scheme 98: Driver or Passenger Seat Back Cushion Heater Replacement (KA1)
CalloutComponent Name
Preliminary Procedure Remove the front seat. Refer to Front Seat Replacement - Bucket (AQ9) or Front Seat Replacement - Bucket (W2E) . Remove the front seat adjuster switch bezel. Refer to Driver or Passenger Seat Adjuster Switch Bezel Replacement (AQ9) or Driver or Passenger Seat Adjuster Switch Bezel Replacement (W2E) . Remove the front seat inner recliner finish cover. Refer to Driver or Passenger Seat Inner Recliner Finish Cover Replacement (W2E) or Driver or Passenger Seat Inner Recliner Finish Cover Replacement (AQ9) . Remove the front seat back cushion finish panel. Refer to Driver or Passenger Seat Back Cushion Finish Panel Replacement (W2E) or Driver or Passenger Seat Back Cushion Finish Panel Replacement (AQ9) . Remove the front seat head restraint. Refer to Driver or Passenger Seat Head Restraint Replacement (W2E) or Driver or Passenger Seat Head Restraint Replacement (AQ9) . Remove the front seat head restraint guides. Refer to Front Seat Head Restraint Guide Replacement (W2E) or Front Seat Head Restraint Guide Replacement (AQ9) . Remove the front seat inner adjuster rear finish cover.
1Seat Back Cushion Cover Procedure Disengage the j-channel retainers from the seat back cushion frame. Disconnect the blower from the seat back cushion pad. Disconnect the electrical connectors that attach to the seat back cushion, if equipped. Remove the seat back cushion cover and pad from the seat cushion frame as an assembly. Pull the cover away from the pad to disengage the retainers
2Front Seat Back Cushion Heater Procedure: Remove the seat back heater from the seat back cushion pad by sliding it through the upper portion of the seat back cushion pad.

Scheme 99

Scheme 99: Driver Seat Cushion Heater Replacement (KA1)
Scheme 99: Driver Seat Cushion Heater Replacement (KA1)
CalloutComponent Name
WARNING: Refer to SIR Warning . Preliminary Procedure Remove the front seat. Refer to Front Seat Replacement - Bucket (AQ9) or Front Seat Replacement - Bucket (W2E) . Remove the front seat cushion cover and pad. Refer to Front Seat Cushion Cover and Pad Replacement (W2E) or Front Seat Cushion Cover and Pad Replacement (AQ9) .
1Seat Cushion Cover Procedure Disengage the j-channel retainers from the seat cushion frame. Disconnect the blower from the seat cushion pad. Disconnect the electrical connectors that attach to the seat cushion, if equipped. Remove the seat cushion cover and pad from the seat cushion frame as an assembly. Pull the cover away from the pad to disengage the retainers
2Front Seat Cushion Heater Procedure: Remove the seat cushion heater from the seat cushion pad by sliding it through the seat cushion pad.
WARNING
Refer to SIR Warning .

Scheme 100

Scheme 100: Passenger Seat Cushion Heater Replacement (KA1)
Scheme 100: Passenger Seat Cushion Heater Replacement (KA1)
CalloutComponent Name
WARNING: Refer to SIR Warning Preliminary Procedure Remove the front seat. Refer to Front Seat Replacement - Bucket (AQ9) or Front Seat Replacement - Bucket (W2E) . Remove the seat cushion cover. Refer to Front Seat Cushion Cover and Pad Replacement (W2E) or Front Seat Cushion Cover and Pad Replacement (AQ9) .
1Inflatable Restraint Front Passenger Presence System Assembly WARNING: Replace the passenger presence system as a complete assembly to prevent possible injury to the occupant. All the components in the service kit are assembled and calibrated as a unit. Using only some of the components in the service kit will cause the passenger presence system to operate improperly. WARNING: To avoid personal injury, perform a preload test on the passenger presence system whenever you remove or replace the seat cushion trim. Failure to do so may cause the system to malfunction. Procedures Preload Test the inflatable restraint passenger presence system whenever the seat cushion or any component of the passenger presence system is removed. Refer to Control Module References . Program the inflatable restraint passenger presence system after replacement. Refer to Control Module References . Tip: The passenger presence system is an integral part of the pad on the passenger seat cushion. The sensor, module and seat cushion pad must be replaced as a unit. Note the routing of the wiring harness and connector location for installation.
WARNING
Refer to SIR Warning
WARNING
Replace the passenger presence system as a complete assembly to prevent possible injury to the occupant. All the components in the service kit are assembled and calibrated as a unit. Using only some of the components in the service kit will cause the passenger presence system to operate improperly.
WARNING
To avoid personal injury, perform a preload test on the passenger presence system whenever you remove or replace the seat cushion trim. Failure to do so may cause the system to malfunction.

Scheme 101

Scheme 101: Driver or Passenger Seat Back Ventilation Heating and Cooling Blower Replacement (KB6)
Scheme 101: Driver or Passenger Seat Back Ventilation Heating and Cooling Blower Replacement (KB6)
CalloutComponent Name
Preliminary Procedure Remove the front seat. Refer to Front Seat Replacement - Bucket (AQ9) or Front Seat Replacement - Bucket (W2E) . Remove the front seat back cushion cover and pad. Refer to Front Seat Back Cushion Cover and Cushion Pad Replacement (W2E) or Front Seat Back Cushion Cover and Cushion Pad Replacement (AQ9) .
1Front Seat Back Cushion Cover and Pad Refer to Front Seat Back Cushion Cover and Cushion Pad Replacement (W2E) or Front Seat Back Cushion Cover and Cushion Pad Replacement (AQ9) .
2Front Seat Back Cushion Ventilation Heating and Cooling Blower Procedure: Disconnect the electrical connector.

Scheme 102

Scheme 102: Driver or Passenger Seat Back Ventilation Heating and Cooling Blower Replacement (W2E)
Scheme 102: Driver or Passenger Seat Back Ventilation Heating and Cooling Blower Replacement (W2E)
CalloutComponent Name
Preliminary Procedure Remove the front seat head restraint. Refer to Driver or Passenger Seat Head Restraint Replacement (W2E) or Driver or Passenger Seat Head Restraint Replacement (AQ9) . Remove the front seat head restraint guide. Refer to Front Seat Head Restraint Guide Replacement (W2E) or Front Seat Head Restraint Guide Replacement (AQ9) . Remove the front seat back cushion cover and pad. Refer to Front Seat Back Cushion Cover and Cushion Pad Replacement (W2E) or Front Seat Back Cushion Cover and Cushion Pad Replacement (AQ9) .
1Front Seat Back Ventilation Heating and Cooling Blower Procedure Disconnect the electrical connector. Twist the fan assembly counter clockwise, then slide it rearward separating it from the seat back cushion pad. Transfer components as necessary.

Scheme 103

Scheme 103: Driver or Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement (KB6)
Scheme 103: Driver or Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement (KB6)
CalloutComponent Name
Preliminary Procedure Remove the front seat. Refer to Front Seat Replacement - Bucket (AQ9) or Front Seat Replacement - Bucket (W2E) . Remove the front seat cushion cover and pad. Refer to Front Seat Cushion Cover and Pad Replacement (W2E) or Front Seat Cushion Cover and Pad Replacement (AQ9) .
1Front Seat Cushion Ventilation Heating and Cooling Blower Screw (Qty: 2) CAUTION: Refer to Fastener Caution . Tighten: 3 N.m (27 lb in)
2Front Seat Cushion Ventilation Heating and Cooling Blower Procedure: Disconnect the electrical connector.
CAUTION
Refer to Fastener Caution .

Scheme 104

Scheme 104: Driver or Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement (W2E)
Scheme 104: Driver or Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement (W2E)
CalloutComponent Name
Preliminary Procedure Remove the front seat. Refer to Front Seat Replacement - Bucket (AQ9) or Front Seat Replacement - Bucket (W2E) . Remove the front seat cushion cover and pad. Refer to Front Seat Cushion Cover and Pad Replacement (W2E) or Front Seat Cushion Cover and Pad Replacement (AQ9) .
1Front Seat Cushion Ventilation Heating and Cooling Blower Procedure Disconnect the electrical connector. Twist the fan assembly counterclockwise, then slide it downward separating it from the seat cushion pad. Transfer components as necessary.

Heated Seat Components

The heated seats consist of the following components

  1. Left heated seat switch
  2. Left vented seat switch
  3. Right heated seat switch
  4. Right vented seat switch
  5. HVAC control panel
  6. Memory seat module
  7. Left seat cushion heating element
  8. Left seat back heating element
  9. Left seat cushion temperature sensor
  10. Right seat cushion heating element
  11. Right seat back heating element
  12. Right seat cushion temperature sensor
  13. MISC IGN Fuse 10 A

Heated Seat Operation

The driver and passenger heated seats are controlled by separate heated seat switches. Both switches are located in the integrated center stack (ICS). When a heated seat switch is pressed, a message is sent via the CAN graphical interface (CGI) serial data line to the radio. The radio then serves as a gateway to transmit the message to the memory seat module (MSM) via GMLAN serial data indicating the heated seat command. In response to this signal, the MSM then applies or removes battery voltage through the element supply voltage circuit of the seat heating elements. The MSM then sends a serial data message back to the radio to gateway the information to the ICS to either illuminate or turn off the appropriate temperature indicator.

Temperature Regulation

The heated seat system is designed to warm the seat cushion and seat back to 3 different temperature settings; High, MED, and Low. The memory seat module (MSM) monitors the seat temperature through the temperature sensor signal circuits and the temperature sensors (thermistor) that are located in the seat cushion and the seat back. The temperature sensors are variable resistors, their resistance varies as the temperature of the seat changes. When the temperature sensor resistance indicates to the MSM that the seat has reached the desired temperature, the module opens the ground path of the seat heating elements through the heated seat element control circuit. The module will then cycle the element control circuit open and closed in order to maintain the desired temperature.

Vented Seat Operation

The vented seat operation is designed to draw cabin air around and away from the occupant through small holes in the seat cushion and seat back covers, through channels in the foam pad, and then through the blower motor exhausting the waste air under the seat cushion.

The driver and passenger vented seats are controlled by separate vented seat switches located in the integrated center stack (ICS) with the radio and HVAC controls. With the ignition ON, Ignition voltage is supplied to the driver and passenger seat blower motors through the MISC IGN fuse located in the underhood fuse block. Ground from G200 is provided to the driver seat blower motors, while G201 provides ground for the passenger seat blower motors. When a vented seat switch is pressed, a message is sent via the CAN graphical interface (CGI) serial data line to the radio. The radio then serves as a gateway to transmit the message to the memory seat module (MSM) via the GMLAN serial data line indicating the vented seat command. In response to this message, the MSM applies a low side pulse width modulation (PWM) signal through the blower motor control circuits to the seat cushion and seat back blower motors indicating the vented seat command. The logic in the blower motors then sets the blower speed to the switch set point. Both blower motors run drawing cabin air around and away from occupant. The MSM then sends a serial data message back to the radio to gateway the information back to the ICS to either illuminate or turn off the appropriate switch indicator.

Load Management

The electrical power management function is designed to monitor the vehicle electrical load and determine when the battery is potentially in a high discharge condition. The heated seat system is one of the vehicle loads that is subject to reduction during a battery discharge condition. For more information on load management refer to Electrical Power Management Description and Operation .

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