B1479

Step 1: Perform visual inspection of the washer fluid reservoir and locate the fluid level sensor (typically integrated into reservoir cap or mounted in reservoir side). Check for damaged wiring, corroded connectors, or physical damage to sensor or float mechanism.

Step 2: Using a multimeter, check for proper voltage supply at the sensor connector (typically 5V or 12V reference) with ignition on. Verify ground circuit continuity by measuring resistance between sensor ground pin and battery negative (should be less than 1 ohm).

Step 3: Disconnect the sensor connector and measure resistance across the sensor terminals while manually moving the float from empty to full position. Resistance should change smoothly (typical range 50-300 ohms depending on manufacturer). If reading is infinite or shorted to zero, sensor is faulty.

Step 4: If sensor tests good, check wiring continuity from sensor connector back to BCM connector using wiring diagram. Look for opens, shorts to ground, or shorts to power (resistance should match wire gauge, typically less than 5 ohms).

Step 5: Clear the code, cycle the ignition, and monitor live data for sensor signal while manually actuating the float. If circuit tests good but code returns without proper signal change, replace the sensor. If all circuits test normal and sensor is replaced but code persists, BCM may require diagnosis or replacement.