Liftgate Release Inoperative Manual Liftgate

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 L/GATE relay. When the liftgate switch signal is activated, the BCM enables the L/GATE relay by applying battery voltage to the liftgate relay circuit and the relay is energized when the BCM grounds the L/GATE relay control circuit. When the relay is energized battery voltage is supplied to the liftgate latch assembly through the liftgate latch control circuit.

Important: Before testing can be performed the liftgate must be opened. Refer to Opening the Liftgate Without Electrical Power for the appropriate procedure.

Schematic Reference

Release Systems Schematics

Connector End View Reference

Vehicle Access Connector End Views

Description and Operation

Rear Hatch/Gate Description and Operation

Electrical Information Reference

Scan Tool Reference

1. Ignition ON, observe the scan tool Liftgate Release Sw parameter while pressing and depressing 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 exterior liftgate switch. The liftgate latch assembly should release the liftgate.

⇒	If the liftgate latch does not release the liftgate, refer to Liftgate Release Malfunction.

Liftgate Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the liftgate switch.
2. Ignition OFF, test for less than 1.0 ohm between the ground circuit terminal 2 and ground.

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

3. Ignition ON, verify the scan tool Liftgate Release parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 1 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 1 and ground. Verify the scan tool Liftgate Release 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 Latch Malfunction

1. Ignition OFF, disconnect the L/GATE relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 30 and ground.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify that a test lamp illuminates between the B+ circuit terminal 87 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

4. Disconnect the harness connector at the liftgate latch assembly.
5. Test for less than 1.0 ohm between the liftgate latch assembly ground circuit terminal 3 and ground

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

6. Connect the harness connector at the liftgate latch assembly.
7. Connect a 15A fused jumper wire between the B+ circuit terminal 87 and the control circuit terminal 30. Verify the liftgate latch assembly is activated.

⇒	If the liftgate latch assembly does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the liftgate latch assembly.

8. Connect a test lamp between the control circuit terminal 85 and ground.
9. Command the liftgate latch to release by pressing and depressing the exterior liftgate 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.

10. Connect a test lamp between the control circuit terminal 86 and B+.
11. Command the liftgate latch to release by pressing and depressing the exterior liftgate 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.

12. If all circuits test normal, test or replace the L/GATE relay.

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 release 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 1 and the ground terminal 2 with the switch in the open position.

⇒	If not the specified value, replace the liftgate exterior switch.

3. Test for less than 2.0 ohms between the signal terminal 1 and the ground terminal 2 with the switch in the closed position.

⇒	If greater than the specified range, replace the liftgate exterior switch.

Relay Test

1. Ignition OFF, disconnect the L/GATE relay.
2. Test for 60-200 ohms of resistance between terminals 85 and 86.

⇒	If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If less than infinite resistance, replace the L/GATE relay.

4. Install a 3-amp fused jumper wire between applicable relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Measure for less than 2 ohms of resistance between terminals 30 and 87.

⇒	If greater than 2 ohms, replace the L/GATE relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.