B2472

Step 1: Perform a visual inspection of the fog lamp switch and its connector for physical damage, corrosion, water intrusion, or loose connections. Check for pushed-back pins or damaged connector locking tabs.

Step 2: Using a digital multimeter, check for proper voltage supply at the fog lamp switch connector (typically battery voltage or 5V reference). Verify ground circuit continuity with key on.

Step 3: Test the fog lamp switch operation by measuring resistance or continuity across switch terminals while cycling the switch through all positions. Compare readings to manufacturer specifications (typically should show continuity in ON position).

Step 4: Check for short to ground or short to power conditions by disconnecting the switch and measuring resistance between the signal wire and ground, then signal wire and power. Should read open circuit (infinite resistance) in both tests.

Step 5: If all circuits test normal, perform a BCM voltage drop test on the switch input circuit to verify proper signal voltage when switch is activated (typically 0V when off, battery voltage or logic level when on).

Step 6: After repairs, clear the code, cycle the fog lamp switch through all positions multiple times, and verify proper fog lamp operation. Road test and rescan to confirm no code return.