GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2007 🢒 CTS 🢒 Seats 🢒 Seat Heating and Cooling 🢒 Heated Seat Inoperative

Test Description

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

  1. This step tests the integrity of the heated seat high/low signal from the rear integration module (RIM). This signal is a momentary 35-millisecond one shot pulse signal that is monitored through a momentary voltage change in the voltmeter when the switch is pressed. In order to accurately recognize the change in voltage, the voltmeter reading should be stable before performing this test.

Step

Action

Values

Yes

No

Schematic Reference: Heated/Cooled Seat Schematics

Connector End View Reference: Heated/Cooled Seat Component Views

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

1

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

--

Go to Step 2

Go to Heated Seats Description and Operation

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

Go to Step 3

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

Does the scan tool display Pressed?

--

Go to Step 4

Go to Step 21

4
  1. Turn OFF the ignition.
  2. Disconnect the heated seat module connector C1.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the battery positive voltage circuit of the heated seat module to a good ground.

Does the voltage measure within the specified range?

10-15 V

Go to Step 5

Go to Step 22

5

Measure the voltage from the battery positive voltage circuit of the heated seat module to the ground circuit of the heated seat module.

Does the voltage measure within the specified range?

10-15 V

Go to Step 6

Go to Step 24

6

Measure the voltage from the ignition 3 voltage circuit of the heated seat module to a good ground.

Does the voltage measure within the specified range?

10-15 V

Go to Step 7

Go to Step 23

7

  1. Turn OFF the ignition.
  2. Connect the heated seat control module connector C1.
  3. Turn ON the ignition, with the engine OFF.
  4. While measuring the voltage from the heated seat high/low signal circuit of the heated seat module to a good ground, activate the heated seat switch.

Does the measured voltage momentarily change state?

--

Go to Step 9

Go to Step 8

8
  1. Turn OFF the ignition.
  2. Disconnect the rear integration module (RIM) connector C2.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the heated seat high/low signal circuit of the module connector to a good ground.

Does the voltage measure within the specified range?

4.5-5.5 V

Go to Step 20

Go to Step 15

9
  1. Disconnect the heated seat module connector C2.
  2. Measure the resistance between the element supply voltage circuit and the element control circuit of the module connector.

Does the resistance measure less than the specified value?

6 ohms

Go to Step 11

Go to Step 10

10
  1. Disconnect the heated seat back connector.
  2. Measure the resistance between the element supply voltage circuit and the element control circuit of the seat back heating element.

Does the resistance measure less than the specified value?

6 ohms

Go to Step 19

Go to Step 18

11

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 signal circuit of the temperature sensor and the low reference circuit of the temperature sensor.

Does the resistance measure within the specified range?

850 ohms - 1150 K ohms

Go to Step 12

Go to Step 19

12

Test the element supply voltage circuit and the element control circuit between the heated seat module and the seat cushion heating element for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 30

Go to Step 13

13

Test the element supply voltage circuit and the element control circuit between the heated seat module and the seat back heating element for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 30

Go to Step 14

14

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

Did you find and correct the condition?

--

Go to Step 30

Go to Step 17

15

Test the heated seat high/low signal circuit between the RIM and the heated seat module for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 30

Go to Step 16

16

Test the heated seat high/low signal circuit between the RIM and the heated seat module for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 30

Go to Step 17

17

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 .

Did you find and correct the condition?

--

Go to Step 30

Go to Step 25

18

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 .

Did you find and correct the condition?

--

Go to Step 30

Go to Step 26

19

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 .

Did you find and correct the condition?

--

Go to Step 30

Go to Step 27

20

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

Did you find and correct the condition?

--

Go to Step 30

Go to Step 28

21

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 .

Did you find and correct the condition?

--

Go to Step 30

Go to Step 29

22

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

Did you complete the repair?

--

Go to Step 30

--

23

Repair the open in the IGN 3 voltage circuit of the heated seat module. Refer to Wiring Repairs .

Did you complete the repair?

--

Go to Step 30

--

24

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

Did you complete the repair?

--

Go to Step 30

--

25

Replace the heated seat module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 30

--

26

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

Did you complete the replacement?

--

Go to Step 30

--

27

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 30

--

28

Replace the RIM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 30

--

29

Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

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