Tail Light Stays on When Car is Off [Reasons & How to Fix]

To drive safely, you need to have functional tail lights because they allow other drivers to see you at night. However, having these lights continuously stay on even when your car is off can be annoying and frustrating. 

Because, this problem can drain your car’s battery, leaving you stranded in the middle of nowhere.

This is why it is necessary for every driver to identify the cause of this problem and how to resolve it with ease.

In this blog post, we will explore some of the common reasons tail lights stay on and what you can do to fix them.

Tail Light Stays on When Car is Off

What is a Tail Light? 

Tail lights are located at the rear of the vehicle, above the bumper. They are red and have white lights beside them to show when the vehicle is in reverse.

This light alerts other drivers of your presence on the road, allowing you to travel securely in the dark. Also, when you brake, the red taillights flare brighter, alerting other vehicles to slow down as well.

Reason Tail Light  Stays On When the Car is Off

1. Faulty Brake Light Switch

If the brake lights remain on when the vehicle is turned off, the brake light switch may still be engaged. This switch is responsible for turning on and off the brake lights, which include the tail lights.  

While the brake foot is motionless, many automobiles include a plastic stopper at the top that disengages the switch.

However, this plastic stopper occasionally breaks or moves, causing the switch to remain engaged and the brake lights to illuminate. In other words, if this switch is faulty or stuck, it will keep the brake lights on even if the car is turned off.

2. Corroded Wiring System

Corroded wiring can also be a reason why your tail light stays on when the car is off. Corrosion can cause an electrical short, which can keep the tail light on.

Corroded wiring can also lead to other electrical problems, so it is essential to fix the issue as soon as possible.

3. Bad Trailer Light Plug

Trailer light plugs might deteriorate and cause the tail lights to remain illuminated. First, make sure that this problem does not occur with other lights on the taillight housing.

Then, if your car has a trailer light plug, unplug it. If the tail lights fail to illuminate, the switch is most likely defective, and the light plug assembly may need to be replaced.

4. Battery Drain

Another reason for a tail light to stay on when the car is off is a battery drain. A battery drain can be caused by leaving the lights on or leaving an electronic device plugged in when the car is off. If the battery is drained, it may not have enough power to start the car, and you may need to jump-start the battery.

How to Fix a Tail Light That Stays On When the Car is Off

1. Examine the Brake Light Switch for Damage

When the switch inside the brake system isn’t working right, your lights won’t turn off. The brake light switch is a small device attached to the brake pedal mechanism. 

The switches and sensors in a braking system are responsible for telling the lights when the pedal is up or down. If either of these is defective, the lights will receive the wrong message. 

Therefore, to ascertain if this is the root of the problem, locate the switch under the dash, towards the top of the brake pedal.

Place a helper behind the car. Check to see if the pedal’s stopper is in place. Push the brake pedal and then press the button on the brake light switch. If this does not turn off the lights, you might need a replacement.

2. Inspect the Wiring

If the brake light switch is not the problem, then you should check the wiring system for any signs of damage or corrosion.

Look for any frayed or broken wires, and replace them if necessary. You may also need to clean the connections and terminals with a wire brush to remove any corrosion.

3. Keep the Brake Pedal Clean

Another reason for the brake light to stay on or become stuck is a blocked brake pedal or failure to close the switch. It might be the result of a faulty rubber stopper or debris/corrosion between the brake switch and pedal.

To avoid this, keep your brake pedal clean and free of rust. If your cleaning does not resolve the issue, perhaps expert maintenance and upkeep would.

4. Disconnect the Battery

If the problem is a battery drain, disconnect the battery when the car is not in use. You can also remove any electronic devices that are plugged in when the car is off. You may need to jump-start the battery or replace it if it is drained.

5. Get Professional Help

If you are not certain about repairing the problem yourself, you can take your vehicle to a professional technician.

They can identify and repair the problem for you. It is not difficult to replace a car battery, but it can be dangerous if you do not know what you are doing.

Read: Misfire at Idle and Low RPM


A faulty brake light switch is one of the major issues that might keep your tail lights on even after you have shut off your car. Another reason for the tail lights to stay on might be a short circuit in the car’s electrical system.

However, to resolve this problem, you might consider checking and replacing the brake light switch or inspecting the tail light wiring and fuses.

If the problem persists, a professional mechanic or automobile specialist should be consulted for a comprehensive diagnosis and repair.