Headlights Flashing When Car Is Off: Causes And Solutions
Generally, the headlights are designed to function only when the car is on. But, the moonlight features of the vehicle may stay turned on for a few minutes after turning off the car. It could be haunting if it keeps flickering. And it can become more haunting if you see headlights flashing when car is off.
So, if you are facing light flickering issues when the car is off, this article will help you to deal with that. We will provide the reasons and solutions to this problem. So, let’s start.
Are Flashing Headlights Normal When Car Is Off?
No, the headlights shouldn’t flash if the car isn’t on. Generally, the light switch of cars has several positions which function in different conditions. This switch position might vary with the car models. But they are pretty similar in all cars:
- Off– when the car is off, the switch will also be off
- Parking– at parking, the parking light will be on
- Auto-light will turn on in the low-light conditions
- On– the light will be on when the car is on
Also, cars with automatic headlight systems will also function in those 4 criteria. That means the headlights should be on when the vehicle is off. The headlights should be on only when you’re driving or parking.
Why the Headlights Flashing When Car Is Off? Causes And Solutions
Due to many causes, the car headlights may flash even if the car is off. The prime reasons are:
- Malfunctioning alarm module
- Loose connections
- Low battery voltage
- Failure of relay
- Defective wiring
- Faulty light switch
- Defective LCM
The illuminating headlights are pretty disturbing when the car is off. That’s why you should hurry with the fixing process of this issue. Here are a detailed discussion of those causes and their particular solutions:
1. Malfunctioning Alarm Module
The alarm module is mainly an anti-theft system for a car. That’s why a defective alarm module will cause the alarm to sound and the flickering headlights continuously. This alarm system will have a tolerance level.
Any fluctuation in the level might cause the activation of the alarm system. If the alarm sensitivity becomes too high or gets damaged, the alarm will activate without valid reasons. This incident will result in flickering or the headlights when the car is off.
- Reset or reduce the sensitivity of the alarm system
- If you can’t fix this module yourself, seek help from a mechanic
2. Loose Connections
Generally, vehicles have a feature moonlight that will stay on for a few minutes after turning off the car. But loose connections in the wiring and terminals can cause the flickering of headlights.
- Check the wiring of the circuits to detect any loose connections
- Tighten all the loose connections
- Replace the faulty relay and blown fuses
3. Low Voltage Battery
The headlight flickering problem due to low battery mainly occurs when you leave the headlight on. If the battery doesn’t have adequate charge, it won’t be able to supply sufficient voltage to the relay. Hence, the light turns off.
But the remaining voltage tries to pull the relay in its position again. As a result, the light will turn on again. This will reduce the voltage again, causing the turning off of the light. And this will keep happening repeatedly.
- Charge the battery sufficiently
- If the battery is dead, you should replace the old one with a new one
- You can use a headlight driver (Our recommendation) to stop flickering for LED headlights. Mainly, this will maintain the supply of steady, consistent, and constant voltage to the headlights
4. Failure Of Relay
The relay is the headlight that controls the low-beam and high-beam circuits. Here is a diagram for headlight relays to better understand this function.
Two of these relays function to supply power for the low-beam fuses. Failure of any of these will result in rapid clicking on and off. Hence, the headlight will flash.
The failure of the relay can occur due to moisture, cold or hot weather, grounding accidentally, etc.
- Pull out the relay and check if there is any corrosion in the relay terminals
- If the relay is already damaged, you have to replace it with a new relay
- Check the wiring connection to ensure the power supply
5. Defective Wiring
Sometimes, owners of vehicles go for aftermarket tuning to modify their cars more. But, due to this, the wire can get mixed, melted together, and short-circuited. This type of defect in wiring may result in the malfunctioning of the car’s headlight.
Due to this, the LCM can get faulty signals for flashing the light when the car is off. Also, the control module may read the “door open” and turn on the headlights even if the door is off.
- Don’t tune your car from any random local dealer
- If you think the flashing headlights are occurring due to defective wiring, ask for help from professional mechanics
6. Faulty Headlight Switch
Due to defective switches, the headlight may also flicker even if the switch is in an “off” position. This occurs when any connector pins will connect unintentionally from behind the switch.
If this happens, it will send misleading signals to the Light Control Module. As a result, the headlight will keep flashing. Many owners use automatic headlight dimmers for this, so the high intensity can’t affect other drivers.
- Turn on the parking switch position; if still the light keeps flickering, that means the light switch is faulty
- Replace the faulty light switch.
Step 1: First, remove the vent, then pull out the switch
Step 2: After that, disconnect it from all the wiring
Step 3: Then install a new switch in the exact reverse process
Check out this Youtube video to understand this replacement process better
7. Defective LCM
The primary function of the Light control module or LCM is to control all vehicle lights. Generally, the light switch will send a signal to the LCM. Then, It will control the fuses and relays to control the function of the car’s lights.
So, any defect in the module can cause the flickering of the headlights, even if the car is off.
- You need to reboot the LCM. For this:
Step 1: Disconnect the terminal connections of the car from the battery
Step 2: Wait for 10-15 minutes so that the system discharges
Step 3: Connect the battery terminals again
- After you finish rebooting the LCM, a few fault codes may arise. To eliminate these fault codes, follow the instructions in the car’s user manual
- If you still can’t solve this problem, look for a mechanic to help you
Frequently Asked Questions (FAQs)
In this FAQs section, we will answer several familiar questions people ask about illuminating headlights when the engine is off.
Do I Need To Worry About The Flashing Headlights Of My Car?
Yes. You should take into account this problem. Because this issue can also be an indication of severe failure of internal parts of the vehicles. Hence, you have taken steps to prevent further major failure of car parts.
Why Is Defective Wiring More Dangerous Cause Of Flashing Headlights?
The defective wiring might be responsible for catching fire and explosion in your car. That’s why you shouldn’t delay fixing after suspecting the flickering lights’ wiring issues. The longer you take, the greater the risk of unexpected accidents.
What Is The Replacement Cost Of The Headlight Switch?
Generally, the replacement cost of the switch will be around $10-$500 without labor costs. This wide range of prices is due to the variations in car models and years.
Almost every car owner faces flickering headlight issues, even when the car is off. This trouble could happen due to faulty wiring, LCM, light switch, relay, and alarm module. Besides, loose wiring connections and low battery voltage can also cause this issue.
Throughout this article, we discussed the solution to every cause of headlights flashing when car is off. If you follow those steps accordingly, you can solve them yourself. But if you cannot fix them, you should take help from professional mechanics.