GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2005 🢒 STS 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Vented Seat Inoperative

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step determines if the vented seat system is totally inoperative.

    2.

  2. This step determines which part of the seat is inoperative, the seat cushion or seat back.

    3.

  3. This step tests the integrity of the pulse width modulation (PWM) serial data signal circuit from the memory seat module. This signal is a momentary 35 millisecond one-shot pulse signal that is displayed by a momentary change in the volt voltmeter when the switch is pressed. Placing the switch in the HIGH HEAT position first before pressing the vented seat switch, will display the greatest amount of change in the measured voltage. In addition, the voltmeter reading should be stable to accurately recognize the change in voltage.

    4.

  4. This step determines if the seat cushion blower has an internal short to ground or voltage.

    5.

  5. This step determines if the seat back blower has an internal short to ground or voltage.

Step

Action

Value(s)

Yes

No

Schematic Reference: Driver Seat Schematics and Passenger Seat Schematics

Connector End View Reference: Power Seat Connector End Views

DEFINITION: This test assumes that Load Shed Level 1 or 2 is not Enabled.

1

Did you review the vented seat operation and perform the necessary inspection?

--

Go to Step 2

Go to Symptoms - Seats

2

Verify that the vented seat inoperative complaint is present.

Does the vented seat system operate as described in the system description and operation?

--

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Are both the driver and front passenger vented seats inoperative?

--

Go to Step 5

Go to Step 4

4

Are both the seat cushion and seat back inoperative?

--

Go to Step 8

Go to Step 17

5
  1. Turn OFF the ignition.
  2. Disconnect the climate control seat module connector C2.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the ignition 3 voltage circuit of the climate control seat module to a good ground.

Does the voltage measure within the specified range?

10-15 V

Go to Step 6

Go to Step 30

6

Measure the voltage from the ignition 3 voltage circuit of the climate control seat module to the ground circuit of the climate control seat module.

Does the voltage measure within the specified range?

10-15 V

Go to Step 7

Go to Step 31

7

Important: If the resistance is measured with the seat still warm, the resistance may vary outside of the specified range since the thermistor resistance varies with temperature.

  1. Turn OFF the ignition.
  2. Disconnect the climate control seat module connector C2.
  3. Measure the resistance between the temperature sensor signal circuit and the temperature sensor low reference circuit of the climate control seat module connector.

Does the resistance measure within the specified range?

600 ohms - 1150 K ohms

Go to Step 25

Go to Step 35

8
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the appropriate Vented Seat parameter in the HVAC Control Module Non-HVAC Data list.
  4. Press the suspect vented seat switch.

Does the Vented Seat parameter change state?

--

Go to Step 9

Go to Step 29

9

  1. Place the appropriate heated/vented seat switch in the HIGH HEAT position.
  2. Measure the voltage from the appropriate pulse width modulation (PWM) serial data signal circuit of the climate control seat module to a good ground.
  3. Press the appropriate vented seat switch.

Does the measured voltage change state?

--

Go to Step 11

Go to Step 10

10
  1. Turn OFF the ignition.
  2. Disconnect the memory seat module (MSM) connector C4.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the appropriate PWM serial data signal circuit of the MSM connector to a good ground.

Does the voltage measure near the specified value?

2.50 V

Go to Step 28

Go to Step 22

11
  1. Place the vented seat switch in the OFF position.
  2. Measure the voltage from the fan speed control circuit of the seat cushion blower motor to a good ground.

Does the voltage measure near the specified value?

10 V

Go to Step 14

Go to Step 12

12

  1. Disconnect the seat cushion blower motor.
  2. From the climate control seat module side of the of the connector, measure the voltage between the blower speed control circuit and a good ground.

Does the voltage measure near the specified value?

10 V

Go to Step 27

Go to Step 13

13

  1. Disconnect the seat back blower motor.
  2. From the climate control seat module side of the of the connector, measure the voltage between the blower speed control circuit and a good ground.

Does the voltage measure near the specified value?

10 V

Go to Step 27

Go to Step 20

14

Measure the voltage from the battery voltage circuit of the blower motor connector to a good ground.

Does the voltage measure within the specified range?

10-15 V

Go to Step 15

Go to Step 32

15

Measure the voltage between the battery voltage circuit of the blower motor connector and the ground circuit of the motor connector.

Does the voltage measure within the specified range?

10-15 V

Go to Step 16

Go to Step 33

16

Important: If the resistance is measured with the seat still warm, the resistance may vary outside of the specified range since the thermistor resistance varies with temperature.

Measure the resistance between the temperature sensor signal circuit and the temperature sensor low reference circuit of the climate control seat module connector.

Does the resistance measure within the specified range?

600 ohms - 1150 K ohms

Go to Step 21

Go to Step 23

17
  1. Turn OFF the ignition.
  2. Disconnect the inoperative seat blower motor.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the battery voltage circuit of the blower motor connector to a good ground.

Does the voltage measure within the specified range?

10-15 V

Go to Step 18

Go to Step 32

18

Measure the voltage between the battery positive voltage circuit of the blower motor connector and the ground circuit of the blower motor connector.

Does the voltage measure within the specified range?

10-15 V

Go to Step 19

Go to Step 33

19

From the climate control seat module side of the of the connector, measure the voltage between the blower speed control circuit and a good ground.

Does the voltage measure near the specified value?

10 V

Go to Step 27

Go to Step 34

20

Test the control circuit of the seat blower motors for the following conditions: Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

    • An open
    • A short to ground
    • A short to battery voltage

Did you find and correct the condition?

--

Go to Step 41

Go to Step 25

21

Test the temperature sensor signal circuit between the climate control seat module and the temperature sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 41

Go to Step 25

22

Test the PWM serial data signal circuit between the memory seat module and the climate control seat module for the following conditions. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

    • An open
    • A short to ground
    • A short to B+

Did you find and correct the condition?

--

Go to Step 41

Go to Step 25

23

Test the signal circuit of the heated/vented seat temperature sensor for a short to voltage and an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 41

Go to Step 24

24

Test the low reference circuit of the heated/vented seat temperature sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 41

Go to Step 26

25

Inspect for poor connections at the harness connector of the climate control seat module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 41

Go to Step 36

26

Inspect for poor connections at the harness connector of the seat cushion heating element and temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 41

Go to Step 37

27

Inspect for poor connections at the harness connector of the inoperative seat blower motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 41

Go to Step 38

28

Inspect for poor connections at the harness connector of the MSM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 41

Go to Step 39

29

Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 41

Go to Step 40

30

Repair the short to ground or open in the ignition 3 voltage circuit of the climate control seat module. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 41

--

31

Repair the open in the ground circuit of the climate control seat module. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 41

--

32

Repair the short to ground or open in the battery voltage circuit of the seat blower motor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 41

--

33

Repair the open in the ground circuit of the seat blower motor. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 41

--

34

Repair the open in the control circuit of the seat blower motors. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 41

--

35

Repair the open in the low reference circuit of the heated/vented seat temperature sensors. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 41

--

36

Replace the climate control seat module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 41

--

37

Replace the seat cushion heating element/temperature sensor. Refer to Driver or Passenger Seat Cushion Heater Replacement .

Did you complete the replacement?

--

Go to Step 41

--

38

Replace the seat blower motor motor. Refer to Driver Seat and Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement or Driver Seat and Passenger Seat Back Ventilation Heating and Cooling Blower Replacement .

Did you complete the replacement?

--

Go to Step 41

--

39

Replace the MSM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 41

--

40

Replace the HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 41

--

41

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2