Turn Signal Relay Guide: Location, Signs of Failure, Replacement Info

Reviewed by

William Guzenski, ASE Certified Master Automobile Technician

Contact Center Manager and Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on February 16th, 2024

Reading Time: 4 minutes
Summary
  • The turn signal relay is a device that controls the car’s turn signal lights.
  • There are four types of relay: DOT, bimetal, hybrid, and solid-state.
  • You’ll know if the relay is bad if your vehicle’s turn signal lights are malfunctioning.
  • Malfunctions often happen due to electrical issues within your vehicle.

Your vehicle has various warning lights to help you communicate with other drivers while on the road. One is the turn signals, which let you alert other drivers when you’re making a turn. Like many other parts of your vehicle, the turn signals can fail over time. One of the reasons why your turn signals might not work is a malfunctioning turn signal relay.

What Is a Turn Signal Relay?

A turn signal relay (also known as a flasher relay) is the electronic device that controls your car’s turn signal lights.

A turn signal relay (also known as a flasher relay) is the electronic device that controls your car’s turn signal lights. The clicking sound when you activate your turn signals usually comes from the turn signal relay.

It’s important to note that on some older vehicles, the flasher is not a relay, but a device that contains a bimetallic strip that heats and contracts in response to current flow.

Many new vehicles do not have a flasher relay. Instead, the turn signals are pulsed on and off by a control module.

Where Is the Turn Signal Relay Located?

The exact location of your turn signal relay depends on the specific vehicle you own. In most cars, the relay is in a junction box along with other relays.

Some vehicle manufacturers label the relay on the fuse box cover to make it easier to identify.

Types of Flasher Units

Flasher relays for turn signals can be classified into four: DOT, bimetal, hybrid, and solid-state.

DOT Flashers

Department of Transportation (DOT) flashers produce a clicking noise for the driver to hear. This type is installed in a metal clip that’s attached to the dash panel.

DOT flashers need current to flow to two bulbs. If one bulb is burnt out, the unit will only produce a steady light instead of a flashing one.

Bimetal Flashers

Bimetal flashers are current-sensitive, so they won’t work if one of their bulbs fails.

They also don’t last as long as hybrid and solid-state flashers.

Hybrid Flashers

This type comes with a flasher relay to operate the unit’s internal electromechanical relay. Its steady electronic timing circuitry helps generate a wide operating voltage and temperature range.

Solid-State Flashers

Solid-state flashers don’t have any moving parts that contribute to mechanical breakdown, which is why this type has the longest life expectancy compared to the other three.

This type has an internal electronic circuit for timing and solid-state power output devices for load-switching.

How Do I Know If My Turn Signal Relay Is Bad?

Your vehicle’s turn signal relay is an essential component for road safety, so it’s crucial to keep it in good condition at all times. Good thing turn signals are one of the easiest car components to troubleshoot.

Here are some bad turn signal relay symptoms to watch for:

Turn Signals Don’t Work

This is the most common symptom of a faulty turn signal relay. Once the relay is broken, the lights won’t turn on with the switch. On some vehicles, the hazard lights also rely on the turn signal relay, so those lights might also cease to function.

Turn Signal Relay Stays On

If your turn signal stays permanently on instead of flashing on and off, it could be a sign that the relay has gone bad. This problem is most likely caused by an electrical issue.

Once you notice this symptom, have your vehicle checked right away. A turn signal light that’s consistently on can confuse other drivers on the road.

How To Diagnose a Failed Turn Signal Relay

First, consult your owner’s manual to see whether your car has a serviceable flasher relay or flasher unit. If the circuit uses a relay, check out the information below to determine what the troubleshooting process typically involves.

What Causes a Blinker Relay to Fail?

Your vehicle might have a faulty switch if the signal lights are not working as they should.

There might also be an issue with the circuit if the parking and hazard lights are operational, but the blinkers aren’t turning on.

How to Test the Turn Signal Relay

The video below demonstrates the typical process for testing an automotive relay of any kind.

How Much Is a Turn Signal Relay?

A high-quality top-notch turn signal relay can be priced anywhere between $10 and $100, depending on its brand and specifications.

If you’re going to ask a mechanic to do the replacement, expect to spend anywhere between $50 and $120 on labor costs. Prices will vary depending on the specific vehicle that you own and the rates in your area.

Your vehicle warning lights help keep you safe on the road, so it’s best to address the issues they develop immediately. Thankfully, there are plenty of high-quality yet affordable aftermarket turn signal relays you can purchase online, which make repairs so much easier.

About The Authors
Reviewed By William Guzenski, ASE Certified Master Automobile Technician

Contact Center Manager and Technical Reviewer at CarParts.com

William “Bill” Guzenski has produced hundreds of how-to videos for the automotive community. He's an ASE Certified Master Automobile Technician, and is affiliated with the Specialty Equipment Market Association (SEMA). He loves attending race events and car shows throughout the country, as well as traveling in his 40-foot motorhome, exploring abandoned mines and ghost towns.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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CarParts.com Research Team and William Guzenski, ASE Certified Master Automobile Technician