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Tahoe / Yukon Service Manual

Power Folding Seat Malfunction (2nd Row)

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

Circuit Number Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
6240 B+ 1 1 — —
5813 B+ 1 1 — —
6808 Control 1 2 — —
2050 Ground — 2 — —
6809 Control 1 3 — —
1450 Ground — 3 — —
6812 Control 1 1 1 —
1050 Ground — 1 — —
1. Both folding seats are inoperative 2. The left 2nd row folding seat is inoperative 3. The right 2nd row folding seat is inoperative

Circuit/System Description The folding 2nd row seats are operated from the folding seat switches located on the passenger side rear panel and on the trim panel in the rear cargo area. Battery voltage is supplied at all times to the folding seat switches through the park enable relay while in a de-energized state. Ground is supplied at all times to the folding seat motors. Battery voltage is also supplied at all times to the folding seat motors through a 20 A fuse located in the X51R Instrument Panel Wiring Harness Junction Block - Right. When a folding seat switch is pressed, battery voltage is applied through the switch contacts and the control circuit to the folding seat motor. The motor runs to move the seat back to the folded position. Diagnostic Aids If there are no electrical issues isolated the concern could be a mechanical issue. Reference Information Rear Seat Schematics Connector End View Reference Master Electrical Component List Description and Operation Power Seats System Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Circuit/System Verification

  1. Ignition ON, transmission in Park.
  2. Verify that no DTCs are set. ⇒ If any DTCs are set Refer to Diagnostic Trouble Code (DTC) List - Vehicle. ⇓ If the DTC is not set
  3. Verify the left and right 2nd row folding seats operate when pressing the appropriate folding seat switch, at the S144A Rear Seat Back Folding Switch - 2nd Row Rear Compartment. ⇒ If one or both folding seats are inoperative Refer to Circuit/System Testing – Test 1 ⇓ If both folding seats operate
  4. Verify the left and right 2nd row folding seats operate when pressing the appropriate folding seat switch, at the switches listed below: S143L Rear Seat Back Folding Switch - 2nd Row Left S143R Rear Seat Back Folding Switch - 2nd Row Right ⇒ If one or both folding seat switched are inoperative Refer to Circuit/System Testing – Test 2 ⇓ If both folding seat switched operate
  5. A fault is currently not present and may be an intermittent condition. Circuit/System Testing Test 1
  6. Ignition OFF, transmission in Park, disconnect the connector at the S144A Rear Seat Back Folding Switch - 2nd Row Rear Compartment, ignition ON.
  7. Verify a test lamp illuminates between the park enable circuit terminal 2 and ground. ⇒ If the test lamp does not illuminate and the circuit fuse is good 2.1. Test circuit 5813 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 2.2. Ignition OFF, disconnect the X2 connector at the X51R Instrument Panel Wiring Harness Junction Block - Right. 2.3. Test for less than 10 Ω between the ground circuit terminal 1 and ground. ⇒ If 10 Ω or greater, repair the open/high resistance in circuit 1050. ⇓ If less than 10 Ω 2.4. Connect the X2 connector and disconnect the X1 connector at the X51R Instrument Panel Wiring Harness Junction Block - Right. 2.5. Ignition ON, transmission out of Park. 2.6. Verify a test lamp does not illuminate between the relay control terminal 32 and ground. ⇒ If the test lamp illuminates, replace the X51R Instrument Panel Wiring Harness Junction Block - Right. ⇓ If the test lamp does not illuminate 2.7. Test circuit 6812 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 2.8. Test circuit 6812 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 2.9. Replace the K9 Body Control Module. ⇒ If the test lamp does not illuminate and the circuit fuse is open 2.1. Test circuit 5813, circuit 6808, and circuit 6809 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 2.2. Replace the appropriate component listed below: M107LR Folding Rear Seat Back Actuator - Left M107RR Folding Rear Seat Back Actuator - Right ⇓ If the test lamp illuminates
  8. Ignition OFF, connect the connector at the S144A Rear Seat Back Folding Switch - 2nd Row Rear Compartment and disconnect the appropriate component listed below: M107LR Folding Rear Seat Back Actuator - Left M107RR Folding Rear Seat Back Actuator - Right
  9. Test for less than 10 Ω between the ground circuit terminals listed below and ground: M107LR Folding Rear Seat Back Actuator - Left = Terminal 2 M107RR Folding Rear Seat Back Actuator - Right = Terminal 2 ⇒ If 10 Ω or greater 4.1. Test the appropriate circuit listed below for an open/high resistance: M107LR Folding Rear Seat Back Actuator - Left = Circuit 2050 M107RR Folding Rear Seat Back Actuator - Right = Circuit 1450 ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 4.2. Repair the open/high resistance in the ground connection. ⇓ If less than 10 Ω
  10. Ignition/Vehicle in Service Mode.
  11. Verify a test lamp illuminates between the B+ circuit terminals listed below and ground: M107LR Folding Rear Seat Back Actuator - Left = Terminal 1 M107RR Folding Rear Seat Back Actuator - Right = Terminal 1 ⇒ If the test lamp does not illuminate 6.1. Test circuit 6240 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 6.2. Test circuit 6240 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 6.3. Verify the fuse is OK and there is voltage at the fuse. ⇓ If the test lamp illuminates
  12. Ignition OFF, connect a test lamp between the control circuit terminals listed below and ground, ignition ON. M107LR Folding Rear Seat Back Actuator - Left = Terminal 3 M107RR Folding Rear Seat Back Actuator - Right = Terminal 3
  13. Verify a test lamp turns ON and OFF when pressing and releasing the appropriate folding seat control switch, at the S144A Rear Seat Back Folding Switch - 2nd Row Rear Compartment. ⇒ If the test lamp does not turn ON and OFF 8.1. Test the appropriate circuits listed below for a short to ground: M107LR Folding Rear Seat Back Actuator - Left = Circuit 6808 M107RR Folding Rear Seat Back Actuator - Right = Circuit 6809 ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 8.2. Test the appropriate circuits listed below for an open/high resistance: M107LR Folding Seat Motor - 2nd Row Left = Circuit 6808 M107RR Folding Rear Seat Back Actuator - Right = Circuit 6809 ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 8.3. Replace the S144A Rear Seat Back Folding Switch - 2nd Row Rear Compartment. ⇓ If the test lamp turns ON and OFF
  14. Replace the appropriate component listed below: M107LR Folding Seat Motor - 2nd Row Left M107RR Folding Rear Seat Back Actuator - Right Test 2
  15. Ignition OFF, transmission in Park, disconnect the appropriate component listed below, ignition ON: S143L Rear Seat Back Folding Switch - 2nd Row Left S143R Rear Seat Back Folding Switch - 2nd Row Right
  16. Verify a test lamp illuminates between the appropriate park enable circuit terminal listed below and ground: S143L Rear Seat Back Folding Switch - 2nd Row Left = Terminal 2 S143R Rear Seat Back Folding Switch - 2nd Row Right = Terminal 2 ⇒ If the test lamp does not illuminate Repair circuit 5813 for an open/high resistance. ⇓ If the test lamp illuminates
  17. Test the appropriate circuits listed below for an open/high resistance: S143L Rear Seat Back Folding Switch - 2nd Row Left = Circuit 6808 S143R Rear Seat Back Folding Switch - 2nd Row Right = Circuit 6809 ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found
  18. Replace the appropriate component listed below: S143L Rear Seat Back Folding Switch - 2nd Row Left S143R Rear Seat Back Folding Switch - 2nd Row Right Repair Instructions Perform the Diagnostic Repair Verification after completing the repair.