GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Avalanche - 4WD 🢒 Body Systems 🢒 Vehicle Access 🢒 Power Door Locks Inoperative - Rear

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

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

I/P Fuse Block B+

3

3

--

--

Driver Door Latch Control

1

1

1

--

Passenger Door Latch Control

2

2

2

--

Lock/Unlock Relay Control

B3135 00

3

3

--

Lock/Unlock Relay Control

B3130 00

3

3

--

Rear Door Latch Control

3

3

3

--

Endgate Lock Actuator Control

3

3

3

--

I/P Fuse Block Ground

--

3

3

--

1. Driver Door Latch Malfunction

2. Passenger Door Latch Malfunction

3. Rear Door/Endgate Latch Malfunction

Circuit/System Description

The BCM is responsible for controlling the left and right rear passenger door lock motors. The BCM, upon receipt of a lock or unlock serial data signal, will control either the rear door lock or unlock relay. When the appropriate door lock relay is energized, the rear power door lock motors will lock or unlock the rear doors and the endgate lock actuator will lock or unlock the endgate.

Reference Information

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Vehicle Access Connector End Views

Description and Operation

Power Door Locks Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Command the doors to LOCK and UNLOCK by using the driver and passenger door lock switches, each door and the endgate should perform the LOCK and UNLOCK function from each switch.

⇒If a rear door or endgate does not LOCK or UNLOCK, refer to Rear Door/Endgate Lock Malfunction.
⇒If both rear door locks and the endgate lock actuator are inoperative, refer to Rear Door Locks Inoperative.

Circuit/System Testing

Rear Door/Endgate Lock Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate rear door latch or endgate lock actuator.
  2. Test for less than 15 ohms between the control circuit terminal listed below and ground:
    3. • Endgate lock actuator terminal A
    • Endgate lock actuator terminal B
    • Left rear door latch terminal 2
    • Left rear door latch terminal 3
    • Right rear door latch terminal 5
    • Right rear door latch terminal 6
    ⇒If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal and the circuit fuse is normal, replace the I/P fuse block.
  3. Ignition ON, connect a test lamp between the control circuit terminals listed below:
    4. • Endgate lock actuator terminal A and terminal B
    • Left rear door latch terminal 2 and terminal 3
    • Right rear door latch terminal 5 and terminal 6
  4. Command the door to LOCK and UNLOCK with a scan tool. The test lamp should briefly illuminate when commanding the LOCK and UNLOCK states.
    5. ⇒If the test lamp remains OFF during either of the commands, test either control circuit for a short to ground. If the circuits test normal, replace the I/P fuse block.
  5. If all circuits test normal, test or replace the rear door latch or endgate lock actuator.

Rear Door Lock Malfunction

  1. Ignition OFF, disconnect the C1 harness connector at the I/P fuse block.
  2. Test for less than 1 ohm between the ground circuit terminal E1 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Connect the C1 harness connector at the I/P fuse block and disconnect the C7 harness connector at the BCM.
  4. Ignition ON, test for greater than 9 volts between the control circuit terminal 9 and ground.
    5. ⇒If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the I/P fuse block
  5. Connect a 15A fused jumper wire between the control circuit terminal 9 and ground. Verify the rear door latches perform the UNLOCK function.
    6. ⇒If the rear door latches do not perform as specified, test the control for a short to voltage. If the circuit tests normal, replace the I/P fuse block.
  6. Verify that a test lamp illuminates between the control circuit terminal 7 and B+.
    7. ⇒If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the I/P fuse block.
  7. Connect a 15A fused jumper wire between the control circuit terminal 7 and B+. Verify the rear door latches perform the LOCK function.
    8. ⇒If the rear door latches do not perform as specified, test the control for a short to ground. If the circuit tests normal, replace the I/P fuse block.
  8. If all circuits test normal, replace the BCM.

Component Testing
  1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
  2. Install a 15A fused jumper wire between one of the control terminals and 12V. Momentarily install a jumper wire between the other control terminal and ground. Reverse the jumper wires at least two times, the door latch should perform the LOCK/UNLOCK functions.
    3. ⇒If it does not perform as specified, replace the door latch

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Rear Door Lock Replacement
    •  Endgate Latch Replacement
    •  Instrument Panel Electrical Center or Junction Block Replacement - Left Side
    •  Control Module References for BCM replacement, programming, and setup