why do my BMW 5 Series G30/G31 (2017-2024) rear lights not work

BMW 5 Series G30/G31 (2017-2024)

Error Codes

1-3 hours

Time

medium

Difficulty

medium

Severity

3 min read

564 words

Problem Statement

The rear lights on a BMW 5 Series G30/G31 (2017-2024) are not functioning, which may affect visibility and safety during driving.

Estimated Time

1-3 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect the battery before working on electrical systems to avoid shorts and shocks.

Symptoms

•Rear lights do not illuminate when headlights are turned on
•Brake lights are not activating when the brake pedal is pressed
•Turn signal indicators at the rear are non-functional
•No warning messages displayed on the dashboard
•Possible blown fuses or burnt bulbs

Diagnostic Steps

1
Check the rear light bulbs for any signs of burning out or damage.
2
Inspect the rear light fuse in the fuse box for continuity.
3
Use an OBD-II scanner to check for any related error codes.
4
Verify the operation of the light switch and ensure it is functioning correctly.
5
Test the wiring harness connections for corrosion or damage.
6
Check the body control module (BCM) for proper function and potential faults.

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

•Remove the rear light assembly cover by unscrewing or unclipping it.
•Take out the bulb socket, remove the old bulb, and insert a new bulb.
•Reassemble the light assembly and reconnect the battery.

Parts Required

•Replacement bulbs
•Fuses (if blown)
•Light switch (if faulty)
•Body control module (if faulty)

Related Faults

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Diagnostic Steps

1
Check the rear light bulbs for any signs of burning out or damage.
2
Inspect the rear light fuse in the fuse box for continuity.
3
Use an OBD-II scanner to check for any related error codes.
4
Verify the operation of the light switch and ensure it is functioning correctly.
5
Test the wiring harness connections for corrosion or damage.
6
Check the body control module (BCM) for proper function and potential faults.

Solution

1. Preparation

Gather tools and parts.
Disconnect the negative battery terminal to ensure safety while working on electrical components.

2. Inspect and Replace Bulbs

Tools Required: Screwdriver or socket set, replacement bulbs (check owner’s manual for specifications).
Remove the rear light assembly cover by unscrewing or unclipping it.
Take out the bulb socket, remove the old bulb, and insert a new bulb.
Reassemble the light assembly and reconnect the battery.

3. Check and Replace Fuses

Tools Required: Fuse puller or needle-nose pliers.
Locate the fuse box (usually found under the dashboard or in the trunk).
Identify the fuse corresponding to the rear lights (refer to the fuse diagram).
Pull the fuse out and visually inspect it. If the metal filament is broken, replace it with a new fuse of the same amp rating.

4. Inspect Wiring and Connectors

Tools Required: Multimeter, electrical contact cleaner.
Examine the wiring harness leading to the rear lights for any signs of damage or fraying.
Clean any corroded connectors with electrical contact cleaner.
Use a multimeter to check for continuity in the wires, ensuring proper voltage is reaching the rear lights.

5. Test Light Switch and BCM

Tools Required: Multimeter.
Test the light switch for proper operation using a multimeter to measure voltage at the switch.
If faulty, replace the switch with a new one.
If necessary, check the BCM for fault codes and replace it if it is malfunctioning.