my BMW 3 Series G20/G21 (2019-2024) blind spot monitoring system is not functioning, what to do?

Solution

1. Preparation

• Gather all necessary tools and parts.
• Ensure the vehicle is parked on a level surface and the ignition is off.
• Disconnect the battery to ensure safety while working on electrical components.

2. Inspect and Clean Sensors

• Tools Required: Torque wrench, clean microfiber cloth, isopropyl alcohol
• Carefully inspect the sensors located in the rear bumper and side mirrors.
• Clean the sensor surfaces gently with a microfiber cloth dampened with isopropyl alcohol to remove any dirt or debris that may obstruct functionality.

3. Check and Repair Wiring

• Tools Required: Multimeter, wire strippers, electrical tape
• Use a multimeter to test the continuity of the wiring harness associated with the blind spot monitoring system.
• Repair any damaged wires using wire strippers and electrical tape. Ensure all connections are secure.

4. Replace Faulty Sensors (if necessary)

• Tools Required: Socket set, torque wrench
• If the diagnostic scan indicated faulty sensors, remove the damaged sensor from the side mirror or rear bumper.
• Install the new sensor by reversing the removal process. Torque bolts to manufacturer specifications (usually around 8-10 Nm).

5. Reconnect Battery and Test System

• Reconnect the battery and start the vehicle.
• Check the settings to confirm that the blind spot monitoring system is enabled.
• Conduct a functional test by driving the vehicle and checking for warning indicators and alerts.