GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

Schematic Reference: Driver Seat Schematics , Passenger Seat Schematics , and Rear Seat Schematics

DEFINITION: One or more of a heated/cooled seat function is inoperative but the switch indicators operate normal.

1

Did you review the Heated/Cooled Seats Description and Operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms - Seats

2

Verify the fault is present.

Does the system operate normally?

--

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

Go to Step 3

3

  1. Turn the ignition ON.
  2. Operate the heat/cool seat switch in all of the operating modes and temperature levels.

Do the heat/cool seat switch indicators operate normally?

--

Go to Step 4

Go to Heated/Cooled Seat Switch Indicator Malfunction

4

Do either of the blower motors operate for at least 4 seconds?

--

Go to Step 7

Go to Step 5

5

  1. Using a DMM, measure the voltage of the mode signal circuit to the CCSM by backprobing the terminal in the body harness to seat harness inline connector.
  2. Start the engine.
  3. Operate the heat/cool seat switch through all of the operating modes.

Does the mode signal circuit voltage begin at battery positive in OFF and change each time the next operating mode is selected?

--

Go to Step 9

Go to Step 6

6

  1. Turn the ignition OFF.
  2. Disconnect the signal converter connector C3.
  3. Using a DMM, measure the mode signal circuit voltage from the affected CCSM at the harness connector terminal.
  4. Turn the ignition ON.

Is the circuit voltage at or near the specified value?

12 V

Go to Step 31

Go to Step 8

7

  1. Cycle the ignition OFF and ON.
  2. Operate the seat in the high heat mode and quickly switch to back only operation.

Does the back only heat mode operate normally for more than 1 minute?

--

Go to Step 12

Go to Step 13

8

Test the mode signal circuit for an open or short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 9

9

  1. Disconnect the CCSM connector C1.
  2. Connect a test lamp from the battery voltage supply circuit terminal in the harness connector to a good ground.

Does the test lamp illuminate?

--

Go to Step 10

Go to Step 28

10

Connect a test lamp from the ignition voltage supply circuit terminal in the CCSM harness connector to a good ground.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 29

11

Connect a test lamp from battery voltage to the ground circuit terminal in the CCSM harness connector.

Does the test lamp illuminate?

--

Go to Step 32

Go to Step 30

12

  1. Cycle the ignition OFF and ON.
  2. Operate the seat in the high cool mode.

Does the seat cushion blower motor operate for at least several seconds?

--

Go to Step 14

Go to Step 18

13

  1. Cycle the ignition OFF and ON.
  2. Operate the seat in the high cool mode.

Does the seat back blower motor operate for at least several seconds?

--

Go to Step 16

Go to Step 20

14

  1. Disconnect the seat cushion heat/cool ventilation blower harness connector.
  2. Measure the resistance through the seat cushion TED from the heat and cool control circuit terminals in the ventilation module connector.

Is the resistance within the specified values?

0.5-7 ohms

Go to Step 15

Go to Step 33

15

Measure the resistance through the seat cushion temperature sensor from the heat and cool control circuit terminals in the ventilation module connector.

Is the resistance within the specified values?

500 ohms-10K ohms

Go to Step 22

Go to Step 33

16

  1. Disconnect the seat back heat/cool ventilation blower harness connector.
  2. Measure the resistance through the seat back TED from the heat and cool control circuit terminals in the ventilation blower connector.

Is the resistance within the specified values?

0.5-7 ohms

Go to Step 17

Go to Step 34

17

Measure the resistance through the seat back temperature sensor from the heat and cool control circuit terminals in the ventilation blower connector.

Is the resistance within the specified values?

500 ohms-10K ohms

Go to Step 23

Go to Step 34

18

  1. Cycle the ignition OFF and ON.
  2. Using a DMM, measure the voltage between the blower motor control and low reference circuits by back probing the terminals in the seat cushion heat/cool ventilation blower harness connector.
  3. Operate the seat in the high cool mode.

Is the voltage greater than the specified value?

4 V

Go to Step 19

Go to Step 24

19

  1. Cycle the ignition OFF and ON.
  2. Disconnect the seat cushion heat/cool ventilation blower connector.
  3. Using a DMM, measure the voltage at the blower motor logic voltage circuit terminal in the harness connector.

Is the voltage at or near the specified value?

12 V

Go to Step 33

Go to Step 25

20

  1. Cycle the ignition OFF and ON.
  2. Using a DMM, measure the voltage between the blower motor control and low reference circuits by back probing the terminals in the seat back heat/cool ventilation blower harness connector
  3. Operate the seat in the high cool mode.

Is the voltage greater than the specified value?

4 V

Go to Step 21

Go to Step 26

21

  1. Cycle the ignition OFF and ON.
  2. Disconnect the seat back heat/cool ventilation blower connector.
  3. Using a DMM, measure the voltage at the blower motor logic voltage circuit terminal in the harness connector.

Is the voltage at or near the specified value?

12 V

Go to Step 34

Go to Step 27

22

Test the seat cushion TED control and temperature sensor circuits from the CCSM to the seat cushion ventilation blower connector for opens or shorts to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 32

23

Test the seat back TED control and temperature sensor circuits from the CCSM to the seat back ventilation blower connector for opens or shorts to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 32

24

Test the seat cushion blower control and low reference circuits from the CCSM to the seat cushion ventilation blower connector for opens or shorts to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 32

25

Test the seat cushion blower logic voltage circuit from the CCSM to the seat cushion ventilation blower connector for an open or short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

 

Go to Step 39

Go to Step 32

26

Test the seat back blower control and low reference circuits from the CCSM to the seat cushion ventilation blower connector for opens or shorts to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 32

27

Test the seat back blower logic voltage circuit from the CCSM to the seat cushion ventilation blower connector for an open or short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

 

Go to Step 39

Go to Step 32

28

Repair the battery voltage supply circuit to the CCSM for an open or short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 39

--

29

Repair the ignition voltage supply circuit to the CCSM for an open or short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 39

--

30

Repair the CCSM ground circuit for an open or high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 39

--

31

Inspect for poor connections at the heat/cool seat switch signal converter. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 35

32

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

Did you find and correct the condition?

--

Go to Step 39

Go to Step 36

33

Inspect for poor connections at the seat cushion ventilation blower connector. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 37

34

Inspect for poor connections at the seat back ventilation blower connector. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 39

Go to Step 38

35

Replace the heat/cool seat switch signal converter. Refer to Passenger Seat Cushion Ventilation Heating and Cooling Module Replacement .

Is the repair complete?

--

Go to Step 39

--

36

Replace the CCSM. Refer to Module Replacement - Seat Climate Control - Front Seat or to Rear Seat Climate Control Module Replacement .

Is the repair complete?

--

Go to Step 39

--

37

Replace the heat/cool seat cushion ventilation blower. Refer to Driver Seat and Passenger Seat Cushion Ventilation Heating and Cooling Blower Replacement or to Rear Seat Cushion Ventilation Heating and Cooling Blower Replacement .

Is the repair complete?

--

Go to Step 39

--

38

Replace the heat/cool seat back ventilation blower. Refer to Driver Seat and Passenger Seat Back Ventilation Heating and Cooling Blower Replacement or to Rear Seat Back Ventilation Heating and Cooling Blower Replacement .

Is the repair complete?

--

Go to Step 39

--

39

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3