GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2008 🢒 STS 🢒 Body Systems 🢒 Vehicle Access 🢒 Trunk 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.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Trunk Relay B+

1

1

--

--

Valet Switch B+

1

1

--

--

Rear Compartment Lid Exterior Release Switch Signal

B3618 02

3

3

--

Rear Compartment Lid Interior Release Switch Signal

B2730 02

2

2

--

Valet Switch Signal

1

1

1

--

Rear Compartment Lid Release Actuator Control

1

1

1

--

Trunk Release Relay Control

1

1

1

--

Rear Compartment Lid Release Actuator Ground

--

1

--

--

Rear Compartment Lid Exterior Release Switch Ground

--

3

3

--

Rear Compartment Lid Interior Release Switch Ground

--

2

2

--

1. Trunk Release Malfunction

2. Trunk Release Interior Switch Malfunction

3 Trunk Release Exterior Switch Malfunction

Circuit/System Description

The interior rear compartment lid release switch receives a signal from the driver window switch. When the interior rear compartment lid release switch is activated the signal circuit is pulled to ground. The driver window switch interprets this and sends a serial data message to the RIM requesting the rear compartment lid be released. The rear integration module (RIM) grounds the trunk release relay control circuit which energizes the relay. The trunk release relay is supplied with battery voltage at all times. With the relay coil energized, the relay switch contacts close allowing battery voltage to flow to the rear compartment lid release actuator causing the rear compartment lid to release. The rear compartment lid release actuator is permanently grounded. When the rear compartment lid release actuator releases the rear compartment lid, the rear compartment lid ajar switch, which is internal the rear compartment lid release actuator, is supplied with ground which causes the trunk ajar switch signal circuit to be pulled low.

The exterior rear compartment lid release switch receives a signal from the remote control door lock receiver (RCDLR). When the exterior rear compartment lid release switch is activated the signal circuit is pulled to ground. The RCDLR interprets this and sends a serial data message to the RIM requesting the rear compartment lid be released. The rear integration module (RIM) grounds the trunk release relay control circuit which energizes the relay. The trunk release relay is supplied with battery voltage at all times. With the relay coil energized, the relay switch contacts close allowing battery voltage to flow to the rear compartment lid release actuator causing the rear compartment lid to release.

Reference Information

Schematic Reference

Release Systems Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Luggage Compartment Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Ignition ON, observe the scan tool Trunk Release Switch parameter located in the driver door switch menu while using the interior rear compartment lid release switch. The parameter should change from Inactive to Active.
    2. ⇒If the parameter does not change, refer to Interior Trunk Release Switch Malfunction.
  2. Observe the scan tool Trunk Release Switch parameter located in the remote control door lock receiver (RCDLR) menu while using the exterior rear compartment lid release switch. The parameter should change from Inactive to Active.
    3. ⇒If the parameter does not change, refer to Exterior Trunk Release Switch Malfunction.
  3. Observe the scan tool Valet Switch parameter located in the instrument panel module (IPM) menu while using the valet switch. The parameter should change from AInactive to Active.
    4. ⇒If the parameter does not change, refer to Valet Switch Malfunction.
  4. Command the trunk to release with a scan tool. The rear compartment lid latch should release the trunk lid.
    5. ⇒If the trunk lid does not release, refer to Trunk Release Malfunction.

Circuit/System Testing

Interior Trunk Release Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the interior rear compartment lid release switch.
  2. Test for less than 10 ohms between the ground circuit terminal 1 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Trunk Release Switch parameter is Inactive.
    4. ⇒If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the driver window switch.
  4. Install a 3A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool Trunk Release Switch parameter is Active.
    5. ⇒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 driver window switch.
  5. If the circuits test normal, test or replace the interior rear compartment lid release switch.

Exterior Trunk Release Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the exterior rear compartment lid release switch.
  2. Test for less than 5 ohms between the ground circuit terminal C and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Trunk Release Switch parameter is Inactive.
    4. ⇒If not the specified value, test the signal circuit terminal A for a short to ground. If the circuit tests normal, replace the RCDLR.
  4. Install a 3A fused jumper wire between the signal circuit terminal A and ground. Verify the scan tool scan tool Trunk Release Switch parameter is Active.
    5. ⇒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 RCDLR.
  5. If all circuits test normal, test or replace the exterior rear compartment lid release switch.

Valet Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the valet switch.
  2. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal A and ground.
    3. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  3. Verify the scan tool Valet Switch parameter is Inactive.
    4. ⇒If not the specified value, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the IPM.
  4. Install a 3A fused jumper wire between the signal circuit terminal B and the B+ circuit terminal A. Verify the scan tool Valet Switch parameter is Active.
    5. ⇒If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the IPM.
  5. If all circuits test normal, test or replace the valet switch.

Trunk Release Malfunction

  1. Ignition OFF, disconnect the TRUNK RELSE relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R33 and ground.
    3. ⇒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 R32 and ground.
    4. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R33 for a short to ground.
  4. Verify that a test lamp illuminates between the B+ circuit terminal R31 and ground.
    5. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  5. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
  6. Test for less than 5 ohms between the ground circuit terminal B and ground.
    7. ⇒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 latch.
  8. Ignition ON, connect a 40A fused jumper wire between the B+ circuit terminal R32 and the control circuit terminal R33. Verify the rear compartment lid release actuator is activated.
    9. ⇒If the rear compartment lid release actuator does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the rear compartment lid latch.
  9. Connect a test lamp between the B+ circuit terminal R31 and the control circuit terminal R35.
  10. Command the Trunk Release Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    11. ⇒If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the RIM.
    ⇒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 RIM.
  11. If all circuits test normal, test or replace the TRUNK RELSE relay.

Component Testing

Relay Test

  1. Ignition OFF, disconnect the TRUNK RELSE relay.
  2. Test for 60-180 ohms between terminals 85 and 86.
    3. ⇒If not within the specified range, replace the relay.
  3. Test for infinite resistance between the following terminals:
    4. • 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 B+. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
    5. ⇒If greater than the specified range, replace the relay.

Rear Compartment Lid Latch

  1. Ignition OFF, disconnect the harness connector at the rear compartment lid latch.
  2. Install a 10A fused jumper wire between the control terminal A and B+. Install a jumper wire between the ground terminal B and ground. Verify the rear compartment lid latch activates.
    3. ⇒If the latch does not perform as specified, replace the rear compartment lid latch.

Interior Rear Compartment Lid Release Switch

  1. Ignition OFF, disconnect the harness connector at the interior rear compartment lid release switch.
  2. Test for infinite resistance between the signal terminal 3 and the ground terminal 1 with the switch in the open position.
    3. ⇒If not the specified value, replace the interior rear compartment lid release switch.
  3. Test for less than 2 ohms between the signal terminal 3 and the ground terminal 1 with the switch in the closed position.
    4. ⇒If greater than the specified range, replace the interior rear compartment lid release switch.

Exterior Rear Compartment Lid Release Switch

  1. Ignition OFF, disconnect the harness connector at the exterior rear compartment lid release switch.
  2. Test for infinite resistance between the signal terminal A and the ground terminal C with the switch in the open position.
    3. ⇒If not the specified value, replace the exterior rear compartment lid release 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.
    4. ⇒If greater than the specified range, replace the exterior rear compartment lid release switch.

Valet Switch

  1. Ignition OFF, disconnect the harness connector at the valet switch.
  2. Test for infinite resistance between the signal terminal B and the B+ terminal A with the switch in the open position.
    3. ⇒If not the specified value, replace the valet switch.
  3. Test for less than 2 ohms between the signal terminal B and the B+ terminal A with the switch in the closed position.
    4. ⇒If greater than the specified range, replace the valet switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Rear Compartment Lid Switch Replacement
    •  Relay Replacement
    •  Rear Compartment Lid Valet Lock Out Switch Replacement
    •  Control Module References for DDSA, RCDLR, or RIM replacement, setup, and programming