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Liftgate Release Inoperative



LIFTGATE RELEASE INOPERATIVE

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 Initial Inspection and Diagnostic Overview.





DIAGNOSTIC FAULT INFORMATION

CIRCUIT/SYSTEM DESCRIPTION
The liftgate can be released by operating the liftgate release switch or pressing the liftgate release button on the key fob. The gear selector may be in any position, but vehicle speed must equal 0 for the liftgate to release.

Pressing the Liftgate Switch closes a contact providing a ground for the Rear Closure Handle Switch Open Signal circuit. The BCM will detect the voltage drop and command voltage to be supplied to the Liftgate Latch Relay Supply Voltage circuit thus energizing the Liftgate Relay which provides voltage to the Liftgate Latch releasing the liftgate.

CIRCUIT/SYSTEM TESTING

Liftgate Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the Liftgate Switch.
2. Ignition OFF, test for less than 1 ohm for resistance 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 Ext Trunk/Liftglass Rel Sw is Inactive.
- If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3-A fused jumper wire between the signal circuit terminal A and ground. Verify the scan tool Ext Trunk/Liftglass Rel Sw 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 harness connector at the I/P Fuse Block.
2. Connect a test lamp between the B+ circuit terminal 1 and ground.
3. Ignition ON, the test lamp should illuminate.
- If the test lamp is always OFF and the BATT MAIN fuse is good, test the B+ circuit for an open/high resistance. If the circuit tests normal, replace the Underhood Fuse Block.
- If the test lamp is always OFF and the BATT MAIN fuse is open, test the B+ circuit for a short to ground, if the circuit tests normal, replace the I/P Fuse Block.
4. Connect a test lamp between the Liftgate Latch Relay Supply Voltage circuit terminal 20 and ground.
5. Command the Liftgate Latch to release by pressing the Liftgate Switch. The test lamp should turn ON and OFF while pressing and depressing the Liftgate Switch.
- If the test lamp is always ON, test the voltage circuit for a short to voltage. If the circuit tests normal, replace the BCM.
- If the test lamp is always OFF, test the voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
6. Connect a test lamp between the Liftgate Latch Relay Coil Control circuit terminal 9 and B+.
7. Command the Liftgate Latch to release by pressing the Liftgate Switch. The test lamp should turn ON and OFF while pressing and depressing the Liftgate Switch.
- 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
8. Ignition OFF, connect the harness connector at the I/P fuse Block. Disconnect the harness connector at the Liftgate Latch.
9. Test for less than 1.0 ohm of resistance between the Liftgate Latch ground circuit terminal 3 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance
10. Connect a test lamp between the control circuit terminal 1 and ground..
11. Ignition ON, command the Liftgate Latch to release by pressing the Liftgate Switch. The test lamp should turn ON and OFF while pressing and depressing the Liftgate Switch
- 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 L/GATE circuit fuse is good, test the control circuit for an open/high resistance, if the circuit tests normal, test or replace the I/P Fuse Block.
- If the test lamp is always OFF and the L/GATE circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the Liftgate Latch.
12. If all circuits test normal, test or replace the Liftgate Latch.

COMPONENT TESTING

Liftgate Latch
1. Ignition OFF, disconnect the harness connector at the liftgate latch.
2. Install a 15-amp fused jumper wire between the control circuit terminal 1 and 12 volts. Install a jumper wire between the ground circuit terminal 3 and ground. Verify the release actuator activates.
- If the actuator does not perform as specified, replace the liftgate latch.

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 circuit 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 circuit 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.
- Liftgate Outside Handle Replacement
- Control Module References for BCM replacement, setup, and programming Verification Tests Programming and Relearning
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