B1373

Step 1: Perform visual inspection of the illuminated entry relay location, checking for signs of water intrusion, corrosion, burnt terminals, or damaged wiring. Remove the relay and inspect the socket terminals for damage or corrosion.

Step 2: With relay removed and ignition off, use a digital multimeter to measure voltage on the relay control circuit terminal at the socket. Reading should be 0V or near 0V; if battery voltage is present, there is a short to power in the wiring harness between the BCM and relay socket.

Step 3: Inspect the wiring harness along its entire length from BCM to relay socket, paying special attention to areas where harness passes through body panels, near sharp edges, or where it may contact hot components. Look for chafed insulation or pinched wires.

Step 4: If wiring checks good, test the suspected relay with an ohmmeter to check for internal shorts between terminals. Replace relay if internal resistance indicates a short between coil and switched terminals.

Step 5: If all external components test good, perform BCM relay driver circuit test per manufacturer specifications using a scan tool with bidirectional controls to activate the relay circuit while monitoring voltage and current draw.

Step 6: After repairs, clear codes, cycle the ignition and door locks multiple times to verify proper illuminated entry operation, then road test and verify code does not return.