hazard lights blinking when car is off

Hazard lights blinking when the car is off- Causes!


The flashing indicators that are located inside the indicator switch assembly are called hazard lights or warning lights. As opposed to the turning signal, which only uses one indicator, this feature will make both lights flash simultaneously.

Hazard lights are easily turned on and off by just pressing a button with a red triangle printed on it. Most drivers turn it on when they want to warn other drivers regarding a mechanical failure or any obstacles on the road.

hazard lights blinking when car is off

Hazard lights can also develop faults just like any other components in a car. This is when they will blink even if the car is locked and turned off.

You’re curious as to why the danger lights blink when you lock or turn off your vehicle and how to fix this? Discover all these causes by reading on.

Causes of Hazard Lights Blinking When a Car Is Off

There are several causes for hazard lights to blink when a car is off which are:

  1. Fault in the circuit.

Usually, a group of hard wirings combined with a flasher or sensors control the hazard lights. If the hazard lights of your car stay on, and it is either blinking without a command, or just blinking in an irregular rhythm, then there is a high probability of a grounding problem in your car’s switch circuit. Check the relay in your switch circuit assembly which has a small resistor inside it. 

This resistor will give surety of proper flashing or blinking. If there are grounding faults inside the relay it will cause either irregular blinking, leaving hazard lights on or just blinking without any command.

This could be because of a bad signal relay, bad relay grounding or a bad hazard switch. If the problem is the relay, just change it by a professional as it might cause battery drainage in less than a day. The relay is located just behind the radio in the dash in most of the cars. A car electrician would be able to check the fuse that is burnt. 

  • Door issues.

The hazard lights may all stay on if any of your car doors are not completely locked. Your car sensor will alert you to this thing. This issue can be fixed if you just close all the doors properly or you might need to fix the door hinges if the doors can’t get properly locked.

  • Corrosion.

Corrosion that builds up over time in cars can cause the hazard lights to turn on and off, or just stays on. Corrosion is common in places where the climate is cold or places where it rains a lot and receives humidity as well. 

If corrosion is the issue, you need to have your car properly inspected by a professional. The connections of hazardous lights underneath the hood need to be checked. Make sure to inspect your car’s fuse box for hazard switches and taillamps as well as for corroded hazard lights.

After finding corrosion, you need to start cleaning up. First, disconnect your car’s battery and then start cleaning the metal contact points with a mild sandpaper. You can check for products for cleaning the corrosion online.

  • Faulty alarm module

Basically, an alarm module is used to receive signals from sensors installed in your car so that it knows when break-in is applied. A faulty alarm module may trigger wrong alarms because of which it will flash the hazard lights. 

Some other factors such as a Weak or sensitive sensor, faulty control module, nonfunctional key fob, faulty hood latch, and corroded battery terminals can also cause false alarms in the car.

  • Disconnected siren

Disconnected sirens can also cause hazard lights to flash or stay on. This issue is strongly dependent on the history of the car’s ownership as they might have disconnected the siren. That is why the alarm control module might wrongly interpret it as an applied break-in and then turns the alarm on. So, as the siren is now disconnected, the hazard lights will flash, and you might not hear any sort of sound. 

  • Faulty hazard switch

Out of all the causes, there can be a good chance that a faulty hazard switch might be causing the hazard lights to flash on because with the help of this button you can turn on hazard lights. There is a higher chance that the electrical switch behind the casing is faulty. 

Sometimes the button can also get stuck and might not come out. This is why the light stays on. There is also a good chance that the toggle on the back of the button controlling the power and flow of electricity might be faulty.

Whenever you press the hazard lights button, a gateway will close which enables the proper power supply, and when the gateway is open the power will be cut off. 

Pressing the button on and off many times to check if the hazard switch is working is important and also to see if the hazard lights turn on and off in a proper consistent way with the pressing of the button.

Now, if you know that the button is at fault or it is just stuck, you should take a pin or you can take a skinny blade as well to insert in the seam or groove of the button and then tug it slowly to pull backwards or just completely release the button. You can use WD-40 as well for removing any sort of moisture, debris or dryness causing the button to get stuck. 

Any fault in the toggle can be easily fixed by WD-40, but it sometimes still causes the problem and needs to be replaced in that case. It will cost you around $100-$120, depending on your car’s make and model.

Can hazard lights drain the battery?

Yes, hazard lights will drain your car’s battery like any other electrical device that is left on such as radios, headlights etc. If you leave hazard lights on for a time even with your car’s engine not running, it will use battery power.

However, hazard lights are also designed in such a way that it uses less power and if you leave them on for some time it will not affect your car’s battery.

If the hazard lights are blinking even when the car is off, then there is a problem. This will drain your car’s battery and that is why you might need to disconnect your car’s battery whenever you stop your vehicle. Sometimes, there are possible electrical problems which you will have to address quickly or there would be severe effects. These lights will cause the car’s battery to drain faster than it usually would. 

There might be a possibility that it can ruin your car’s battery and you will need to replace it. Don’t get lazy! Look for a technician that could fix this problem.


A: Yes, certain modern cars now have dangers that, like airbags, will deploy automatically in the event of a collision. They might also turn on if you press the brakes abruptly, such as in an emergency stop. Nowadays, many vehicles come equipped with hazard lights that activate automatically when the driver presses the brakes firmly. Its sole purpose is to alert oncoming traffic that something is about to happen and that they should exercise caution (and slow down).

A: A button located close to the steering wheel is used to turn on the hazard lights. All of the vehicle’s turn signals will simultaneously brighten and begin flashing in a rhythmic pattern when the switch is turned on. Some cars (often European models) have automated danger warning lights that come on when the car is braking hard or in an accident.

A: Hazard lights are distinctive lights on a car that flash on and off to alert other drivers to a potentially hazardous scenario. They serve as a warning that the vehicle flashing its lights may be a danger. The four indicators (front and rear, right and left) start blinking simultaneously when the lights are turned on. The purpose of hazard lights is to warn oncoming traffic of potential dangers. 

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