B1435

Step 1: Perform visual inspection of wiper relay, fuse box, and associated wiring. Check for obvious damage, corrosion, or loose connections at relay socket and BCM connectors. Verify correct relay is installed and properly seated.

Step 2: Using a multimeter, test relay coil resistance (typically 70-120 ohms depending on vehicle). Remove relay and check for continuity across coil terminals. If open circuit found, replace relay and retest.

Step 3: With relay removed, use multimeter to check for battery voltage at relay socket power supply terminal (key on). Check for proper ground at relay socket ground terminal. Voltage should be present per manufacturer specifications.

Step 4: Backprobe BCM connector and measure voltage on relay control circuit wire while commanding wipers on high and low speeds. Should see switching voltage (typically 12V or ground depending on design). If no switching signal, suspect BCM or wiring issue.

Step 5: Perform continuity test on wiring between BCM and relay socket with connectors disconnected. Check for open circuits, shorts to ground, or shorts to power. Repair any damaged wiring as needed.

Step 6: Clear codes, reinstall components, and operate wipers through all speed settings. Monitor for code return and verify proper high/low speed operation. If code returns with known-good relay and wiring, BCM replacement may be necessary.