B1339

Step 1: Perform visual inspection of all wiring harnesses between BCM and chime module, looking for damaged insulation, melted wires, or evidence of harness routing near hot or sharp components. Check for aftermarket installations that may have damaged harnesses.

Step 2: Disconnect the chime module connector and measure voltage on the chime input request circuit wire at the harness side using a digital multimeter. Reading should be 0V or low voltage (typically less than 1V). If battery voltage (12V+) is present with module disconnected, wiring harness has short to power.

Step 3: If no voltage present at disconnected harness, reconnect chime module and backprobe the circuit at the module connector with key on. If voltage jumps to battery voltage, chime module has internal short. If voltage remains normal, perform BCM output driver test using bidirectional controls to command chime on/off.

Step 4: Inspect all connector terminals for corrosion, pushed-back pins, or cross-circuit contamination. Pay special attention to connectors exposed to moisture (under dash, door jambs). Use electrical contact cleaner and verify proper terminal tension.

Step 5: If harness short is confirmed, trace the affected circuit through its entire routing path using wiring diagrams. Use resistance measurements between the circuit and power sources to isolate the exact location of the short. Repair or replace damaged harness section.

Step 6: After repairs, clear codes and verify proper chime operation by testing all chime functions (key-in-ignition, lights-on, door-ajar, seatbelt warning). Monitor for code return during test drive and verify BCM can properly control chime activation.