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Trunk Release Inoperative




Trunk 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

When the ignition is ON, the Body Control Module (BCM) supplies battery positive voltage to the rear compartment lid release switch through the trunk release switch supply voltage circuit. When the rear compartment lid release switch is operated, the trunk release supply voltage circuit is grounded through the switch ground circuit and the voltage is pulled low within the BCM. In response, the BCM applies battery positive voltage to the trunk release relay control circuit, which energizes the coil side of the trunk relay. The switch side of the trunk relay then closes, supplying battery positive voltage through the relay and the relay controlled output circuit to the rear compartment lid latch. The rear compartment lid latch, then releases the rear compartment lid so that it may be manually raised to an open position.

Reference Information
Schematic Reference

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

Component Connector End Views (Connector Views)
Description and Operation

Luggage Compartment 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 trunk release switch. The parameter should change between Active and Inactive.

• If the parameters do not change, refer to Trunk Release Switch Inoperative.

2. Command the trunk release with a scan tool. The rear compartment lid release actuator should release the deck lid.

• If the release actuator does not release the deck lid, refer to Release Actuator Inoperative.

Circuit/System Testing

Trunk Release Switch Inoperative
1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Test for less than 1 ohm between the ground circuit terminal 8 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 9 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 9 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 headlamp switch.

Release Actuator Inoperative
1. Ignition OFF, disconnect the TRUNK relay.
2. Test for less than 1 ohm between the relay coil ground circuit terminal and ground.

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

3. Ignition ON, verify that a test lamp does not illuminate between the relay controlled output circuit terminal and ground.

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

4. Verify that a test lamp illuminates between the relay switch B+ circuit terminal and ground.

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

5. Ignition OFF, disconnect the harness connector at the rear compartment lid release actuator.
6. 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.

7. Connect the harness connector at the rear compartment lid release actuator.
8. Ignition ON, connect a 10A fused jumper wire between the relay switch B+ circuit terminal and the relay controlled output circuit terminal. Verify the rear compartment lid release actuator is activated.

• If the rear compartment lid release actuator does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the rear compartment lid release actuator.

9. Connect a test lamp between the relay coil control circuit terminal and the relay coil ground circuit terminal.
10. Command the trunk release ON and OFF with a scan tool. 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.

11. If all circuits test normal, test or replace the TRUNK relay.

Component Testing

Relay Test
1. Ignition OFF, disconnect the TRUNK relay.
2. Test for 60-180 ohms between terminals 85 and 86.

• If 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 not the specified value, replace the relay.

4. Install a 25A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.

• If greater than the specified range, replace the relay.

Rear Compartment Lid Release Actuator

1. Ignition OFF, disconnect the harness connector at the rear compartment release actuator.
2. Install a 10-amp fused jumper wire between the control terminal 4 and 12 volts. Install a jumper wire between the ground terminal 3 and ground. Verify the rear compartment release actuator activates.

• If the latch does not perform as specified, replace the rear compartment release actuator.

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

• If not the specified value, replace the headlamp switch.

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

• If greater than the specified range, replace the headlamp switch.

Repair Instructions

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

* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Headlamp Switch Replacement (Impala) (Service and Repair)
* Rear Compartment Lid Latch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming
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