GM Service Manual Online
For 1990-2009 cars only

Heated Seat Inoperative Driver

Step

Action

Values

Yes

No

Schematic Reference: Driver Seat Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you review the Heated Seat System Description and Operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms - Seat Heating and Cooling

2

  1. Turn ON the ignition.
  2. Operate the heated seat switch to the low and high positions.

Does the heated seat system operate normal?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Do the low and high switch indicators operate normal?

--

Go to Step 6

Go to Step 4

4

  1. Disconnect the heated seat switch connector.
  2. Connect a test lamp from the ignition voltage supply circuit terminal in the harness connector to ground.

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 11

5

Connect a test lamp from the ignition voltage supply circuit terminal to the ground circuit terminal in the heated seat switch harness connector.

Does the test lamp illuminate?

--

Go to Step 15

Go to Step 12

6

  1. Disconnect the seat cushion heater element 4-way connector C319.
  2. Connect a test lamp from the battery voltage supply circuit terminal in the seat harness connector to ground.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 13

7

Connect a test lamp from the battery voltage supply circuit terminal to the ground circuit terminal in the C319 seat harness connector.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 14

8

  1. Using a DMM measure the resistance through the heated seat switch from the heated seat switch signal circuit terminal to the ground circuit terminal in the C319 seat harness connector.
  2. Operate the heated seat switch in the high and low positions.

Is the resistance at or near the specified values?

Hi 2.5K ohms

Lo 4.9K ohms

Go to Step 10

Go to Step 9

9

  1. Disconnect the heated seat switch connector.
  2. Test the heated seat switch high/low signal circuit for an open or short to ground. Refer to Circuit Testing and to Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 15

10

  1. Disconnect the seat back heater element 2-way connector.
  2. Test the resistance through the seat back heater element.

Is the resistance within the specified values?

0.5-2 ohms

Go to Step 16

Go to Step 17

11

Repair the open or short to ground in the ignition voltage supply circuit to the heated seat switch. Refer to Circuit Testing and to Wiring Repairs .

Is the repair complete?

--

Go to Step 21

--

12

Repair the open or high resistance in heated seat switch ground circuit. Refer to Circuit Testing and to Wiring Repairs .

Is the repair complete?

--

Go to Step 21

--

13

Repair the open or short to ground in the battery voltage supply circuit to the heated seat control module. Refer to Circuit Testing and to Wiring Repairs .

Is the repair complete?

--

Go to Step 21

--

14

Repair the open or high resistance in the heated seat control module ground circuit. Refer to Circuit Testing and to Wiring Repairs .

Is the repair complete?

--

Go to Step 21

--

15

Inspect for poor connections at the heated seat switch. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 18

16

Inspect for poor connections at the seat cushion heater element. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 19

17

Inspect for poor connections at the seat back heater element. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs .

Did you find and correct the condition?

--

Go to Step 21

Go to Step 20

18

Replace the heated seat switch. Refer to Lumbar Switch Replacement .

Is the repair complete?

--

Go to Step 21

--

19

Replace the seat cushion heater element. Refer to Driver or Passenger Seat Cushion Heater Replacement .

Is the repair complete?

--

Go to Step 21

--

20

Replace the seat back heater element. Refer to Driver or Passenger Seat Back Cushion Heater Replacement .

Is the repair complete?

--

Go to Step 21

--

21

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3

Heated Seat Inoperative Passenger

Step

Action

Values

Yes

No

Schematic Reference: Passenger Seat Schematics

Connector End View Reference: Power Seat Connector End Views

1

Did you review the Heated Seat System Description and Operation and perform the necessary inspections?

--

Go to Step 2

Go to Symptoms - Seat Heating and Cooling

2

  1. Turn ON the ignition.
  2. Buckle the passenger seat belt.
  3. Operate the heated seat switch to the low and high positions.

Does the heated seat system operate normal?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

Do the low and high switch indicators operate normal?

--

Go to Step 7

Go to Step 4

4

  1. Disconnect the heated seat switch connector.
  2. Connect a test lamp from the ignition voltage supply circuit terminal in the harness connector to ground.

Does the test lamp illuminate?

--

Go to Step 5

Go to Step 13

5

Connect a test lamp from the ignition voltage supply circuit terminal to the ground circuit terminal in the heated seat switch harness connector.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 14

6

  1. Unbuckle the passenger seat belt.
  2. Connect a test lamp from the ignition voltage supply circuit terminal to the seat belt switch signal circuit terminal in the heated seat switch harness connector.
  3. Buckle the passenger seat belt.

Does the test lamp go OFF when the seat belt is buckled?

--

Go to Step 18

Go to Step 15

7

  1. Disconnect the seat cushion heater element 4-way connector C318.
  2. Connect a test lamp from the battery voltage supply circuit terminal in the seat harness connector to ground.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 16

8

Connect a test lamp from the battery voltage supply circuit terminal to the ground circuit terminal in the C318 seat harness connector.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 17

9

  1. Connect the seat cushion heater element connector C318.
  2. Using a DMM measure the voltage of the heated seat switch signal circuit by back probing terminal C.
  3. Operate the heated seat switch in the Hi and Lo positions.

Is the signal circuit voltage greater than the specified value in the Hi and Lo switch positions?

7.5 V

Go to Step 12

Go to Step 10

10

  1. Disconnect the seat cushion heater element connector C318.
  2. Using a DMM measure the resistance to ground of heated seat switch signal circuit from the heater element connector half terminal C.

Is the resistance greater than the specified value?

7K ohms

Go to Step 11

Go to Step 19

11

  1. Disconnect the heated seat switch connector.
  2. Test the heated seat switch high/low signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 18

12

  1. Disconnect the seat back heater element 2-way connector.
  2. Test the resistance through the seat back heater element.

Is the resistance within the specified values?

0.5-2 ohms

Go to Step 19

Go to Step 20

13

Repair the open or short to ground in the ignition voltage supply circuit to the heated seat switch. Refer to Circuit Testing and Wiring Repairs .

Is the repair complete?

--

Go to Step 25

--

14

Repair the open or high resistance in heated seat switch ground circuit. Refer to Circuit Testing and Wiring Repairs .

Is the repair complete?

--

Go to Step 25

--

15

Test the seat belt switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 24

16

Repair the open or short to ground in the battery voltage supply circuit to the heated seat control module. Refer to Circuit Testing and Wiring Repairs .

Is the repair complete?

--

Go to Step 25

--

17

Repair the open or high resistance in the heated seat control module ground circuit. Refer to Circuit Testing and Wiring Repairs .

Is the repair complete?

--

Go to Step 25

--

18

Inspect for poor connections at the heated seat switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 21

19

Inspect for poor connections at the seat cushion heater element. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 22

20

Inspect for poor connections at the seat back heater element. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 23

21

Replace the heated seat switch. Refer to Lumbar Switch Replacement .

Is the repair complete?

--

Go to Step 25

--

22

Replace the seat cushion heater element. Refer to Driver or Passenger Seat Cushion Heater Replacement .

Is the repair complete?

--

Go to Step 25

--

23

Replace the seat back heater element. Refer to Driver or Passenger Seat Back Cushion Heater Replacement .

Is the repair complete?

--

Go to Step 25

--

24

Replace the seat belt buckle. Refer to Front Seat Belt Buckle Replacement .

Is the repair complete?

--

Go to Step 25

 

25

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3