how to fix the rear windshield wiper on BMW 3 Series G20/G21 (2019-2024) not working

BMW 3 Series G20/G21 (2019-2024)

Error Codes

1-2 hours

Time

medium

Difficulty

medium

Severity

3 min read

569 words

Problem Statement

The rear windshield wiper on a BMW 3 Series G20/G21 (2019-2024) is not functioning, which may indicate issues with the wiper motor, wiring, or control system.

Estimated Time

1-2 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems.
•Ensure the vehicle is in park and the ignition is off during repair.

Symptoms

•Rear wiper does not activate when switched on
•No noise or movement from the wiper motor
•Wiper blade appears stuck or does not return to the parked position
•Possible water accumulation or streaking on the rear windshield
•Related warning message on the vehicle's display (if applicable)

Diagnostic Steps

1
Check the rear wiper fuse in the fuse box for continuity using a multimeter.
2
Use an OBD-II scanner to check for error codes related to the rear wiper system.
3
Inspect the rear wiper switch for proper operation.
4
Verify the power supply to the wiper motor by connecting a multimeter to the motor connector.
5
Inspect the wiring harness for any visible damage or disconnection.
6
Test the rear wiper motor directly by applying power to it outside the vehicle.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Multimeter
•Socket set
•Trim removal tool
•Torque wrench

Parts Required

•Rear wiper motor (if faulty)
•Wiper blade (if worn)

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Diagnostic Steps

1
Check the rear wiper fuse in the fuse box for continuity using a multimeter.
2
Use an OBD-II scanner to check for error codes related to the rear wiper system.
3
Inspect the rear wiper switch for proper operation.
4
Verify the power supply to the wiper motor by connecting a multimeter to the motor connector.
5
Inspect the wiring harness for any visible damage or disconnection.
6
Test the rear wiper motor directly by applying power to it outside the vehicle.

Solution

1. Preparation

Gather all necessary tools and parts.
Ensure the vehicle is parked on a level surface and the ignition is turned off.
Disconnect the negative battery terminal to prevent electrical shorts.

2. Access the Rear Wiper Motor

Remove the rear wiper arm by loosening the retaining nut with a socket set.
Carefully pull the wiper arm off the spindle; use a puller if necessary.
Remove the interior trim panel from the rear hatch to access the wiper motor (typically requires a trim removal tool).

3. Inspect and Test the Wiper Motor

Locate the rear wiper motor.
Inspect the motor for any physical damage or corrosion.
Using a multimeter, check for voltage at the motor connector while activating the rear wiper switch.
- If no voltage is present, troubleshoot back to the switch or wiring.
If voltage is present and the motor does not operate, it may need replacement.

4. Replace the Wiper Motor (if necessary)

Disconnect the motor wiring harness.
Remove the mounting bolts securing the wiper motor using a socket set.
Install the new wiper motor by reversing the removal steps.
Reconnect the wiring harness securely.

5. Reassemble Components

Reattach the interior trim panel, ensuring all clips and fasteners are securely in place.
Reinstall the rear wiper arm onto the spindle and tighten the retaining nut to the manufacturer's torque specifications (typically around 15-20 Nm).
Reconnect the negative battery terminal.