GM Service Manual Online
For 1990-2009 cars only

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.

DTC Descriptor

DTC B3641: Trunk Close Switch Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Trunk Key Switch Signal

1

1

1

--

Trunk Release Control Signal

1

1

B3265

--

Trunk Release Switch Signal -- Exterior

B3618

1

1

--

Trunk Release Switch Signal -- Interior

1

1

1

--

Rear Compartment Lid Pull Down Actuator Signal

B1297

B1297

B1297

--

Rear Compartment Lid Pull Down Actuator B+

1

1

1

--

Rear Compartment Lid Release Close Switch B+

1

1

B3641

--

Trunk Release Switch Supply Voltage

1

1

1

--

Rear Compartment Lid Pull Down Actuator Ground

1

1

1

--

Rear Compartment Lid Release Switch Exterior Ground

1

1

1

--

Rear Compartment Lid Release Switch Interior Ground

1

1

1

--

Rear Compartment Lid Release Close Switch Ground

1

1

1

--

1. Trunk Release Inoperative

Circuit Description

The folding top control (FTC) module checks the integrity of the signal circuits from the rear compartment lid release close switch at least once every 300 milliseconds. The rear compartment lid release close switch has a constant battery positive voltage supplied. Pressing the rear compartment lid release close switch will apply the battery positive voltage to the rear compartment lid release close switch signal circuit to the FTC module. The FTC module monitors the signal request and will operate the rear compartment lid when battery positive voltage is received. For more detailed information concerning power folding top operation refer to Power Folding Top Description and Operation .

Conditions for Running the DTC

    • Battery voltage must be between 9-16 volts.
    • DTC B1327 is not set as current.

Conditions for Setting the DTC

The FTC module detects a short to battery in the rear compartment lid release close switch circuit for more than 5 seconds.

Actions Taken When the DTC Sets

    • FTC module stores DTC B3641 to memory.
    • The rear compartment lid pull-down feature will be inactive from the rear compartment lid release close switch.

Conditions for Clearing the DTC

    • The condition responsible for setting the DTC no longer exists.
    • You issue a scan tool CLEAR DTCs command.
    • A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

Diagnostic Aids

A rear compartment lid release close switch that is held or stuck in the closed position for more than 5 seconds will set DTC B3641.

Reference Information

Schematic Reference

Release Systems Schematics

Connector End View Reference

Vehicle Access Connector End Views

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the rear compartment lid release/close switch.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal D and ground.
  3. 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 signal circuit terminal A for a short to ground.
  4. Verify that a test lamp does not illuminate between the signal circuit terminal A and ground.
  5. If the test lamp illuminates, test the signal circuit terminal A for a short to voltage. If the circuit tests normal, replace the FTC module.
  6. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal D and signal circuit terminal A.
  7. If the test lamp does not illuminate, test the signal circuit terminal A for an open/high resistance. If the circuit tests normal, replace the FTC module.
  8. If all circuits test normal, test or replace the rear compartment lid release/close switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Rear Compartment Lid Latch Replacement
    •  Control Module References for FTC module replacement, setup, and programming