Liftgate Release Inoperative

Liftgate Release Inoperative

Diagnostic Instructions

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



Diagnostic Fault Information






Circuit/System Description

The liftgate switch is an input to the body control module (BCM). The BCM supplies battery voltage to the signal circuit and when the liftgate switch is activated the signal circuit voltage goes low. The BCM controls the liftgate latch assembly through the liftgate RLYS relay. When the liftgate switch signal is activated, the BCM enables the RLYS relay by applying battery voltage to the liftgate relay circuit and the relay is energized when the BCM grounds the RLYS relay control circuit. When the relay is energized battery voltage is supplied to the liftgate latch assembly through the liftgate latch control circuit.


Diagnostic Aids

Before testing can be performed, the liftgate must be opened. Refer to Opening the Liftgate Without Electrical Power (Procedures) for the appropriate procedure.


Reference Information
Schematic Reference

Release Systems Schematics (Release Systems Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Rear Hatch/Gate 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)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

1. Ignition ON, observe the scan tool Int Trunk/Liftglass Sw parameter while pressing and releasing the liftgate release switch. The reading should change between Active and Inactive.

• If the reading does not change, Refer to Liftgate Release Switch Malfunction.

2. Command the liftgate release by pressing the liftgate release switch. The liftgate latch assembly should release the liftgate.

• If the liftgate latch does not release the liftgate, Refer to Liftgate Release Malfunction.




Circuit/System Testing


Liftgate Release Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the liftgate release switch.
2. Test for less than 1 ohm 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 the scan tool Int Trunk/Liftglass Sw parameter is Inactive.

• If not the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool Int Trunk/Liftglass Sw parameter is Active.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM

5. If all circuits test normal, test or replace the liftgate release switch.



Liftgate Release Malfunction
1. Ignition OFF, disconnect the X1 harness connector at the I/P fuse block.
2. Connect a test lamp between the control circuit terminal 5 and B+.
3. Command the liftgate latch assembly ON and OFF by pressing and releasing the liftgate release switch, the test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

4. Connect a test lamp between the control circuit terminal 6 and ground.
5. Command the liftgate latch assembly ON and OFF by pressing and releasing the liftgate release switch, the test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

6. Ignition OFF, connect the X1 harness connector at the I/P fuse block. Disconnect the harness connector at the liftgate latch assembly.
7. Test for less than 1 ohm between the ground circuit terminal 3 and ground.

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

8. Connect a test lamp between the control circuit terminal 1 and ground.
9. Command the liftgate latch assembly ON and OFF by pressing and releasing the liftgate release switch. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the I/P fuse block.
• If the test lamp is always OFF and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace I/P fuse block.
• If the test lamp is always OFF and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the liftgate latch assembly.

10. If all circuits test normal, test or replace the liftgate latch assembly.



Component Testing


Liftgate Latch Assembly
1. Ignition OFF, disconnect the harness connector at the liftgate latch assembly.
2. Install a 20-amp fused jumper wire between the control terminal 1 and 12 volts. Install a jumper wire between the ground terminal 3 and ground. Verify the liftgate latch actuator activates.

• If the actuator does not perform as specified, replace the liftgate latch assembly.




Liftgate Release Switch
1. Ignition OFF, disconnect the harness connector at the liftgate release switch.
2. Test for infinite resistance between the signal terminal B and the ground terminal A with the switch in the open position.

• If not the specified value, replace the liftgate release switch.

3. Test for less than 2 ohms between the signal terminal B and the ground terminal A with the switch in the closed position.

• If greater than the specified range, replace the liftgate release switch.




Repair Instructions

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

* Liftgate Outside Handle Replacement (Service and Repair)
* Instrument Panel Wiring Harness Junction Block Replacement (Instrument Panel Wiring Harness Junction Block Replacement)
* Liftgate Latch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming