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Home >> Hummer >> 2009 >> H3 L5-3.7L >> Repair and Diagnosis >> Body and Frame >> Seats >> Seat Temperature Element >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Heated Seat Inoperative

Heated Seat Inoperative




Heated Seat Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description

Battery voltage is supplied at all times to the heated seat module from the HTD/SEATS 20A fuse located in the underhood fuse block. Ignition voltage is supplied to the lumbar adjuster switch through the PWR HTR SWITCH 10A fuse also located in the underhood fuse block. When the heated seat switch is in either the HI or LO heat position, ignition voltage is applied through one of the internal resistors of the switch and the switch signal circuit to the heated seat module. In response to this signal, the heated seat module applies battery voltage through the heater element control circuit to the seat cushion and seat back heater elements for heated seat operation.

Reference Information
Schematic Reference

Heated/Cooled Seat Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Heated Seats Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Circuit/System Verification

Driver Seat

Ignition ON, operate the heated seat switch to the high and low heat positions. The heated seat should activate and the switch indicator should illuminate when the switch is in the high or low heat positions.

If the heated seat switch indicator does not illuminate or is always illuminated refer to the Driver Heated Seat Switch Circuit Test.
If the heated seat switch indicator operates normal and the heated seat is inoperative, refer to the Heated Seat Circuit Test.

Passenger Seat

Ignition ON, seat belt buckled, operate the heated seat switch to the high and low heat positions. The heated seat should activate and the heated seat switch indicator should illuminate when the switch is in the high or low heat positions.

If the heated seat switch indicator does not illuminate or is always illuminated, refer to the Passenger Heated Seat Switch Circuit Test.
If the heated seat switch indicator operates normal and the heated seat is inoperative, refer to the Heated Seat Circuit Test.

Circuit/System Testing

Driver Heated Seat Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the driver seat lumbar adjuster switch.
2. Test for less than 5 Ohms between the ground circuit terminal A and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

4. If all circuits test normal, test or replace the driver seat lumbar adjuster switch.

Passenger Heated Seat Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the passenger seat lumbar adjuster switch.
2. Test for less than 5 Ohms between the ground circuit terminal A and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal C and ground.

• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

4. Connect a test lamp between the ignition circuit terminal C and the signal circuit terminal D.
5. Ignition ON, buckle and unbuckle the seat belt. The test lamp should turn OFF when buckled and ON when unbuckled.

• If the test lamp is always OFF, test the signal circuit for an open/high resistance. If the circuit tests normal, test or replace the seat belt buckle.
• If the test lamp is always ON, test the signal circuit for a short to ground. If the circuit tests normal, test or replace the seat belt buckle.

6. If all circuits test normal, test or replace the passenger seat lumbar adjuster switch.

Heated Seat Circuit Test
1. Ignition OFF, disconnect the harness connector at the appropriate heated seat module.
2. Test for less than 5 Ohms between the ground circuit terminal 4 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Ignition OFF, test for 5.39 k - 6.49 kOhms between the signal circuit terminal 6 and ground with the heated seat switch in the HIGH heat position.

• If less than the specified value, test the signal circuit for a short to ground. If the circuit tests normal, test or replace the lumbar adjuster switch.
• If greater than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, test or replace the lumbar adjuster switch.

5. Test for 7.14 k - 8.73 kOhms between the signal circuit terminal 6 and the ground with the heated seat switch in the LOW heat position.

• If not within the specified range, test or replace the lumbar adjuster switch.

6. Test for 2 k - 30 kOhms between the signal circuit terminal 2 and the ground circuit terminal 4.

• If not within the specified range, replace the seat cushion heater element.

7. Disconnect the harness connector at the seat back heater element.
8. Test for less than 5 Ohms between the ground circuit terminal B and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

9. At the seat back heater element; test for 1.5 - 5 Ohms between terminal A and terminal B.

• If not within the specified range, replace the seat back heater element.

10. Connect the harness connector at the seat back heater element.
11. At the heated seat module connector; test for 1.5 - 5 Ohms between the control circuit terminal 7 and ground.

• If not within the specified range, test or replace the seat cushion heater element.

12. If all circuits test normal, replace the heated seat module.

Component Testing

Heated Seat Switch
1. Ignition OFF, disconnect the harness connector at the appropriate seat lumbar adjuster switch.
2. Test for infinite resistance between the terminals listed below with the switch in the open position:

* Signal terminal B and ignition terminal C
* Ignition terminal C and ground terminal A

• If not the specified value, replace the lumbar adjuster switch.

3. Test for 2.5 kOhms between the signal terminal B and the ignition terminal C with the switch in the HIGH heat position.

• If not the specified value, replace the lumbar adjuster switch.

4. Test for 4.9 kOhms between the signal terminal B and the ignition l terminal C with the switch in the LOW heat position.

• If not the specified value, replace the lumbar adjuster switch.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Driver or Passenger Seat Back Cushion Heater Replacement (Driver or Passenger Seat Back Cushion Heater Replacement)
* Driver or Passenger Seat Cushion Heater Replacement (Driver or Passenger Seat Cushion Heater Replacement)
* Control Module References (Programming and Relearning) for heated seat module replacement, programming, and setup

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