The lights are an essential component of any vehicle. The headlights allow the driver to see at night, dashboard lights provide early warnings of mechanical problems, etc. The lights on a BMW, unlike many other parts, have not changed very much in the last few generations. But that does not mean that BMW lights are without problems and one issue that can appear is that the lights will flicker when they are turned off. But what does it mean when a BMWs lights flicker when turned off?
A faulty light control switch, faulty rain-light sensor, or a faulty Lamp Control Module may cause the headlights on a BMW to flicker, even if they are turned off. If the dashboard warning lights are randomly flickering, it may be due to low battery voltage or a faulty alternator.
Read on to discover what may cause the headlights and the dashboard warning lights to flicker when they are switched off.
BMW Headlights Flickering When The Switch Is Turned Off
Flickering headlights on a BMW may be caused by several factors. If the issue is not resolved, it may lead to battery draining if the flickering continues when the car is turned off. If this is happening on your vehicle, the following may be the cause.
Faulty Light Switch
The light switch on a BMW will have the following selections:
- Off – The lights of the vehicle are off.
- Automatic – The vehicle’s lights will turn on automatically when the light sensor detects low LUX (light) conditions.
- On – The light on the vehicle is on.
- Parking –The Parking lights on the car are on.
If the headlights are flickering while the switch is in the “off” position, it may be that the connector pins at the back of the light switch are touching. This will send the incorrect signal to the Lamp Control Module (LCM), randomly turning the lights on and off.
To test the switch, move the light switch to the “parking” selection to see if the lights continue to switch on and off. If the light stops flickering, the problem may be the light control switch.
Check out an article and video on replacing the light switch on a BMW here.
Faulty Rain-Light Sensor
When the light control switch is set to “auto” and the headlight is flickering, this may be a faulty rain-light sensor. This sensor is positioned at the back of the rearview mirror and calculates the LUX levels outside of the car. A low LUX level will turn the light on, and a high level will turn the light off.
If the sensor is not functioning correctly, it will send incorrect information to the Lamp Control Module (LCM), randomly turning the lights on and off. The sensor may give an incorrect reading if the windshield has been replaced or the windscreen has been tinted.
The rain-light sensor’s sensitivity can be set in the BMW’s options menu. If setting the sensitivity does not stop the headlights from flickering, the rain-light sensor may be faulty.
Check out an article and video on replacing the rain light sensor on a BMW here.
Faulty Lamp Control Module (LCM)
The LCM controls all the light functions on a BMW, including the odometer and warning lights. The module can be found in the passenger’s footwell and is susceptible to hard bumps and kicks. In BMWs with sunroofs, the roof seal may degrade and allow water into the car’s roof. The water will find its way down the car’s “A” pillar and cause water damage to the LCM.
The LCM receives information from the light control switch and the rain-light sensor. If either sends faulty signals to the LCM, the headlights may flicker. Even if the fault lies with the LCM, the headlights may flicker if the car is switched off.
Below are other common symptoms of a faulty LCM
- Headlights stay on when the vehicle is switched off
- Indicators switch on randomly
- High beams do not work
- Flashing headlights
- False dash warning lights
- Odometer display blank
Simple Fix for Faulty LCM
A simple LCM reboot will fix the flickering light issues in many cases. To perform an LCM reboot, follow the following quick steps.
- Disconnect the terminals from the car’s battery.
- Leave the battery disconnected for 10 to 15 minutes for the system to discharge.
- Reconnect the car’s battery terminals.
After the reboot, the BMW will have a few error codes. To remove the code, follow the instructions in the BMW user Manual. If the flickering headlights persist, the module may be faulty and will need to be replaced.
Check out an article and video on replacing the light control module on a BMW here.
BMW Dashboard Warning Lights Flickering
The LCM controls all the vehicle’s warning lights, but it may not always be at fault if the warning lights are flickering. The following may be causing the dashboard light to switch on and off randomly.
A Faulty Car Battery
The battery voltage is critical in modern cars as this can cause unwanted faults. If your BMW senses a power issue, the LCM will override other modules in the car, such as Dash Module (DM) or the Driver Information Module (DIM). In a BMW, a single sensor may provide information to several other modules in the car.
If one system is overridden, other modules may be at fault and illuminate the warning light. Due to the modules running constant diagnostic tests, your dashboard lights will appear to flicker.
A faulty car battery is a straightforward fix. The easiest way to determine if the battery is faulty is to test the voltage with a battery volt tester. The voltage should read between 12.2 and 13.4 volts. If it is lower than 12 volts, replace the battery.
Loose Battery Terminals
Loose, dirty, or corroded battery terminals can cause your BMW’s dashboard lights to flicker. This will cause similar issues as a damaged or low voltage battery. Inspect the terminals to confirm that they are in fact fastened and ensure the wiring makes contact. If the terminals are dirty, use a terminal brush tool along with a battery terminal cleaner to ensure that you are getting a good connection.
A Faulty Alternator
A faulty alternator will affect the electrical power output for the vehicle. If the alternator is not producing enough current, the battery charge warning light should illuminate, as the battery is not being charged. But due to the low power scenario, other warning lights may begin to flicker.
This may affect the infotainment system and cause the headlights, indicators, and cabin lights to flicker. If the alternator is faulty, it will need to be replaced.
Worn Ground Wires
Your BMW will have a number of ground wires. A fault with any one of the battery, chassis, or alternator ground wires can cause a number of odd electrical issues in your BMW, including flickering lights. It would behoove you to inspect each of your ground wires to confirm that they are all in their proper place and tight. If they are not, clean them and tighten the grounds.
Damaged Or Worn Ignition Switch
An ignition switch starts the whole process of powering up a car. The ignition switch, like any other electronic part, has a number of faults that can occur internally and when this occurs it can keep some devices in the car connected even when the switch is turned off. This will drain the battery very quickly, resulting in flashing warning lights or a vehicle that does not start.
Flickering headlights on a BMW may be due to a damaged light control switch or rain-light sensor sending incorrect information to the LCM. The LCM controls all the light functions of a BMW; if this module is faulty, it can also cause the lights in your BMW to flicker.
If the dashboard warning light is flickering on a BMW, it may be due to a faulty or low voltage battery. If the wiring at the battery terminals is loose, this can also cause the dash warning lights to flicker. If the battery is not charging, the problem may be that the alternator is generating inefficient power for the vehicle’s electronics.