B1617

Step 1: Perform visual inspection of the rear wiper disable switch, its connector, and accessible wiring harness for obvious damage, pinching, chafing against metal, or corrosion. Pay special attention to harness routing near hinges and body seams.

Step 2: Disconnect the rear wiper disable switch connector and measure voltage at the BCM-side connector terminal (switch circuit wire). With ignition on, you should see 0V or a low reference voltage (typically 0-5V). If battery voltage (12V+) is present, the short is in the wiring harness between BCM and switch.

Step 3: If no voltage found in Step 2, test the switch itself by measuring resistance across its terminals in both activated and deactivated positions per manufacturer specifications. Also check for continuity between switch terminals and ground with switch connected to harness to identify internal short to power.

Step 4: Inspect BCM connector terminals for corrosion, bent pins, or signs of water intrusion. Check for voltage on adjacent pins that could indicate cross-circuit contamination within the connector body.

Step 5: If all wiring and connections test normal, perform voltage drop test on the circuit while manipulating the wiring harness to identify intermittent shorts. Move harness at liftgate hinge area, rear pillar, and under rear trim panels while monitoring voltage.

Step 6: After repair, clear codes, cycle the rear wiper disable switch multiple times, and verify battery voltage is no longer present on the circuit. Road test with multiple liftgate open/close cycles to confirm repair.