Liftgate Release Inoperative
Liftgate Release Inoperative
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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/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 release actuator assembly through the LIFTGATE relay. When the liftgate switch signal is activated, the BCM enables the LIFTGATE relay by applying battery voltage to the liftgate relay circuit and the relay is energized when the BCM grounds the LIFTGATE relay control circuit. When the relay is energized battery voltage is supplied to the liftgate release actuator assembly through the liftgate release actuator control circuit.
Circuit/System Verification
1. Ignition ON, observe the scan tool Int Trunk/Liftglass Sw parameter while pressing and releasing the liftgate release switch. The parameter should change between Active and Inactive.
• If the parameter does not change, refer to Liftgate Release Switch Malfunction.
2. Command the liftgate release by pressing the exterior liftgate switch. The liftgate release actuator should release the liftgate.
• If the liftgate release actuator does not release the liftgate, refer to Liftgate Release Malfunction.
Circuit/System Testing
Liftgate Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the liftgate switch.
2. Test for less than 1 ohm between the ground circuit terminal C 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 parameter, test the signal circuit terminal A 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 A and the ground circuit terminal C. 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 switch.
Liftgate Release Malfunction
1. Ignition OFF, disconnect the X2 and X3 harness connectors at the I/P fuse block.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.
• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
3. Connect a test lamp between the relay control circuit terminal 20 and ground.
4. Command the liftgate release actuator ON and OFF by pressing and releasing the liftgate switch. The test lamp should turn ON and OFF while 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.
5. Connect a test lamp between the relay control circuit terminal 9 and B+..
6. Command the liftgate release actuator ON and OFF by pressing and releasing the liftgate switch. The test lamp should turn ON and OFF while 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.
7. Ignition OFF, connect the harness connectors at the I/P fuse block. Disconnect the harness connector at the liftgate release actuator.
8. Test for less than 1.0 ohm between the liftgate release actuator ground circuit terminal 3 and ground
• If greater than the specified range, test the ground circuit for an open/high resistance.
9. Connect a test lamp between the liftgate release actuator control circuit terminal 1 and ground.
10. Command the liftgate release actuator ON and OFF by pressing and releasing the liftgate switch. The test lamp should turn ON and OFF while 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, test the control circuit for an open/high resistance, if the circuit tests normal, replace the I/P fuse block.
11. If all circuits test normal, test or replace the liftgate release actuator.
Component Testing
Liftgate Release Actuator
1. Ignition OFF, disconnect the harness connector at the liftgate release actuator.
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 release actuator activates.
• If the actuator does not perform as specified, replace the liftgate release actuator.
Liftgate Switch
1. Ignition OFF, disconnect the harness connector at the liftgate switch.
2. Test for infinite resistance between the signal terminal A and the ground terminal C with the switch in the open position.
• If not the specified value, replace the liftgate switch.
3. Test for less than 2 ohms between the signal terminal A and the ground terminal C with the switch in the closed position.
• If greater than the specified range, replace the liftgate switch.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Liftgate Outside Handle Replacement
* Instrument Panel Electrical Center or Junction Block Replacement