B1398

Step 1: Visually inspect the driver's power window relay (typically located in under-hood or interior fuse box) for signs of burning, corrosion, or physical damage. Check all associated fuses for continuity using a multimeter.

Step 2: With ignition off, remove the one-touch window relay and test it using a multimeter. Check coil resistance (typically 70-120 ohms) across coil terminals and continuity across normally-open contacts. Apply 12V to coil terminals and verify contacts close with audible click.

Step 3: With relay removed, use a multimeter to check for battery voltage at the relay socket power supply terminal with ignition on. Check for proper ground at ground terminal (less than 0.5 ohms to battery negative). Monitor BCM control signal terminal with test light or multimeter while activating window switch to verify BCM is sending trigger signal.

Step 4: Inspect wiring harness between BCM and relay socket for chafing, pinching, or corrosion. Pay special attention to door jamb areas and under-dash harness routing. Check connector terminals for corrosion, bent pins, or loose fit.

Step 5: If all wiring, relay, and power/ground circuits test normal, verify proper BCM operation by checking for technical service bulletins and performing BCM software updates if available. If no updates exist and all other components test good, BCM replacement may be necessary.

Step 6: After repair, clear codes, cycle the window through full up/down operation multiple times, and perform one-touch auto-up/auto-down initialization procedure per manufacturer specifications. Verify code does not return and one-touch function operates correctly.