[Solved] Turn Signal Light Stays On When Car Is Off

Turn Signal On Car Off

So, you noticed that your turn signal light stays on even when your car is off. Sounds strange! This is usually a common problem in older cars. It can be the left or right signal light, front or rear.

The top reasons for this are

  1. Abad ground connection
  2. Wiring issues
  3. A bad switch
  4. Flasher relay/control unit

A faulty turn signal that stays on can drain your battery, which is why you must solve it quickly. In this guide, we break down exactly how to handle a turn signal that stays on when the car is off.

Key Takeaways

The top reasons why your car signal may stay on when your vehicle is off include:

  • Bad Turn Signal Switch: The switch can become faulty, often due to corrosion.
  • Module Issues: The car's turn signal module, which controls various electrical functions, might malfunction, causing the light to stay on.
  • Wiring Connection Problems: Faulty wiring or electrical connections can keep the turn signal light on and constantly drain the battery.
  • Flasher Relay/Control Unit Malfunction: A defective flasher relay, which regulates the signal light, will also keep the light on.
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Turn Signal On, and Car Is Off Video

Key Causes

Help! Why does my turn signal not turn off? No need to panic. Here are some common reasons your blinker stays on when your car is off.

  • Bad turn signal switch
  • Module issues
  • Faulty wiring
  • Flasher relay/control unit

Let’s dive deeper into each.

1. Bad Turn Signal Switch

The turn signal switch handles the turning on and off of the signal bulbs. When the switch assembly goes bad, it becomes hard to control the turning off of the turn signal light.

Corrosion is the top cause of a bad turn signal switch.

There are chances that the switch is broken. A plastic piece is located inside the switch, aligned with the spring. The signal switch is rendered useless when these components break.

In this case, it wouldn’t signal the system when to work or stop working. If you are experienced, you can open them and put them back in order, or replace them with a new switch assembly.

2. Module

Cars are fitted with different modules that handle the operations of different parts of the automobile system. These modules feature different modes that handle the electrical functions in your car, from locks to A/C controls. Fortunately, the turn signal also has a module.

Some turn signal modules are built with high-grade functions that feature comfort, canceling, and full flash mode.

The turn signal module is designed to go into sleep mode a few minutes after you turn off your vehicle. This is designed to save battery power. If the module is bad, the turn signal will remain and draw power even after you’ve switched off your car.

3. Wiring Connection

A faulty wiring connection is another potential cause for your turn signal light to stay on. If there is a shortage in the wiring/electrical connection of your turn signal, the battery will be drained, with or without turning off the car.

Wire shorting is one of the most complex electrical problems that your car can ever have. This is because it is not only related to a faulty relay, but you will need an advanced auto repairman to detect the drain and fix the problem.

4. Flasher relay/control unit

I can relate to this one because I’ve experienced it! I found out that my left blinker stayed on even though the turn signal was in a neutral position. It became annoying when it wouldn’t go off even after turning off the ignition.

At the end of the diagnosis and repairs, my car’s central alarm control unit was replaced, which resolved the issue.

Because the flasher relay oversees the turning on and off of your turn signal light, faulty ones can affect the turn signal.

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How Do You Fix a Turn Signal That Stays On?

Here are some quick fixes for a turn signal that stays on even after turning off the car.

  • Check wiring
  • Change the turn signal switch
  • Check relays, modules, and control unit

Here’s what you need to know:

1. Change the turn signal switch.

The first thing you should do is to change the turn signal switch. Change the turn signal switch and see if the problem persists.

This simple change may resolve the issue for some. If it does not, then you must progress to the next step.

2. Check your wiring and electrical connections.

Next, check your electrical circuits and connections.

Look out for corrosion, damages, or shorting. Check if you have some wires touching each other, causing a battery drain even when you’ve turned off the ignition.

3. Check relays, modules, and control unit.

You might need the services of an expert to help you out on this. Get your flasher relay, modules, and control unit examined. You must replace all faulty elements.


Your turn signal light staying on when the car is off is usually a minor issue that rarely occurs.

Of course, one option is that there is not a fault, but that you accidentally left the signal on!

You can park your car and still have the turn signal lights blinking. Try turning them off before running diagnostics on them.

However, if the problem persists, then you may have an issue with the wiring, modules, or switch. Unless you have expertise, bring the car to a mechanic for examination and repair.

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Frequently Asked Questions

How do I know if my turn signal relay is bad?

The easiest way to know that your turn signal relay is bad is that your turn signals will stop working. You can also tell your turn signal relay is bad from the hazard lights. Most car companies design the hazard light to rely on the turn signal relay.

What is the most common cause of blinkers staying on?

The most common reason the turn signal light stays on even after turning off the car is a short electrical connection, bad signal switch, bad flasher relay, control unit, and module. Bad wiring and electrical connection are also common causes.

How much does it cost to fix turn signals?

It costs between $200 - $250 to fix your turn signals. This should cover the cost of labor, workmanship, and materials.

Is there a fuse for turn signals?

Yes. All lights in your car need a fuse to function, and the turn signals are no exception. Turn signals have a fuse, and when this fuse is damaged, the turn signal will stop working.

Can leaving your turn signal on drain your battery?

Yes. Leaving your turn signal on will drain your battery. The turn signal draws power from your battery. Prolonged use or leaving them on without use will kill the turn signal.