B1633

Step 1: Perform visual inspection of the driver's door mirror wiring harness, particularly in the door hinge area where flex occurs. Look for pinched, chafed, or damaged insulation that could contact power wires. Check mirror connector for corrosion, water intrusion, or pushed-out terminals.

Step 2: Disconnect the driver's side mirror electrical connector. Using a digital multimeter, check for continuity between the mirror driver circuit terminal (consult wiring diagram) and battery positive with ignition off. There should be no continuity; if present, trace and repair the short in the harness.

Step 3: With mirror disconnected and ignition on, command mirror operation through scan tool bi-directional controls. Measure voltage at the BCM side of the mirror connector driver circuit. Voltage should toggle appropriately with commands; constant battery voltage indicates BCM internal fault.

Step 4: If wiring tests pass, reconnect mirror and monitor current draw with ammeter during mirror operation. Excessive current (typically over 3-5 amps depending on vehicle) indicates internal mirror motor short. Replace mirror assembly if current is excessive.

Step 5: After repair, clear codes and cycle mirror through all positions using switch. Verify proper operation in all directions and confirm no codes return. Check for proper resistance values across mirror motor terminals per manufacturer specifications.