B1683

Step 1: Perform visual inspection of mirror control switch and surrounding trim for physical damage, moisture intrusion, or obvious signs of failure. Remove switch from door panel and inspect connector for bent pins, corrosion, or pushed-back terminals.

Step 2: Using a digital multimeter, check for battery voltage (typically 12V) at the mirror switch power supply wire with ignition on. Verify ground circuit has less than 0.5 ohms resistance to chassis ground.

Step 3: With switch connector disconnected, measure resistance across switch terminals while actuating the switch through all positions (left/right/up/down). Compare readings to manufacturer specifications, typically showing specific resistance values for each position.

Step 4: Check continuity and resistance on all wiring between mirror switch connector and BCM connector using wiring diagram. Wiggle harness through door jamb area while monitoring for intermittent opens.

Step 5: If all wiring and switch test within specifications, use bidirectional controls via scan tool to command mirror movement while monitoring switch input status to isolate BCM internal fault.

Step 6: After repair, clear codes, cycle ignition, operate mirrors through full range of motion, and verify code does not return during road test.