GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

Schematic Reference: Driver Seat Schematics and 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 - Seats

2

Verify that the Heated Seat Inoperative complaint is present.

Does the heated 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

  1. Turn ON the ignition, with the engine OFF.
  2. While observing the heated seat switch temperature indicators, place the heated seat switch in the HIGH and LOW positions.

Do the HI and LO temperature indicators illuminate?

--

Go to Step 4

Go to Step 17

4

  1. Probe the heated seat element supply voltage circuit of the heated seat module with a test lamp that is connected to a good ground.
  2. Place the heated seat switch in the HIGH heat position.

Does the test lamp illuminate?

--

Go to Step 11

Go to Step 5

5

  1. Turn OFF the ignition.
  2. Disconnect the heated seat module.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a test lamp from the battery positive voltage circuit of the heated seat module connector to a good ground.

Does the test lamp illuminate?

--

Go to Step 6

Go to Step 24

6

Connect a test lamp between the battery positive voltage circuit of the heated seat module connector and the ground circuit of the module connector.

Does the test lamp illuminate?

--

Go to Step 7

Go to Step 25

7

  1. Connect a test lamp from the heated seat switch signal circuit of the heated seat module connector to a good ground.
  2. Place the heated seat switch in the HIGH heat position.

Does the test lamp illuminate?

--

Go to Step 8

Go to Step 16

8

  1. Turn OFF the ignition.
  2. Place the heated seat switch in the LOW heat position.
  3. Measure the resistance between the heated seat switch signal circuit of the heated seat module connector and the heated seat high/low signal circuit of the module connector.

Dose the resistance measure near the specified value?

2,500 ohms

Go to Step 9

Go to Step 13

9

  1. Place the heated seat switch in the HIGH heat position.
  2. Measure the resistance between the heated seat switch signal circuit of the heated seat module connector and the heated seat high/low signal circuit of the module connector.

Dose the resistance measure near the specified value?

200 ohms

Go to Step 10

Go to Step 20

10

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

Measure the resistance between the temperature sensor signal circuit of the heated seat module connector and the ground circuit of the module connector.

Does the resistance measure within the specified range?

7,000-11,000 ohms

Go to Step 23

Go to Step 14

11

  1. Disconnect the heated seat module harness connector.
  2. Measure the resistance between the heated seat element supply voltage circuit of the heated seat module and the ground circuit of the heated seat module.

Does the resistance measure less than the specified value?

5 ohms

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

Go to Step 12

12

  1. Disconnect the seat back heating element connector.
  2. Measure the resistance across the back heating element connector.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 19

Go to Step 22

13

Test the heated seat high/low signal circuit between the heated seat switch and the heated seat module for the following conditions:

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

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 30

Go to Step 20

14

Test the ground circuit of the heated 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 30

Go to Step 15

15

Test the signal circuit of the heated seat temperature sensor for the following conditions:

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

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 30

Go to Step 21

16

Test the heated seat switch signal circuit between the heated seat switch and the heated seat module for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 30

Go to Step 20

17

Test the battery positive voltage circuit of the heated seat switch for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 30

Go to Step 18

18

Test the ground circuit heated seat switch for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 30

Go to Step 20

19

Test the ground circuit of the seat heating elements for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 30

Go to Step 21

20

Inspect for poor connections at the harness connector of the heated seat switch. 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 30

Go to Step 26

21

Inspect for poor connections at the harness connector of the heated seat cushion heating element/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 30

Go to Step 27

22

Inspect for poor connections at the harness connector of the heated seat back heating element. 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 30

Go to Step 28

23

Inspect for poor connections at the harness connector of the heated 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 30

Go to Step 29

24

Repair the open or short to ground in the battery positive voltage circuit of the heated seat module. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 30

--

25

Repair the open in the ground circuit of the heated seat module. Refer to Wiring Repairs or Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 30

--

26

Replace the heated seat switch. Refer to Heated Seat Switch Replacement .

Is the repair complete?

--

Go to Step 30

--

27

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

Is the repair complete?

--

Go to Step 30

--

28

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

Is the repair complete?

--

Go to Step 30

--

29

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

Is the repair complete?

--

Go to Step 30

--

30

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2