Bad Turn Signal Light Symptoms

Reviewed by

Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on April 4th, 2024

Reading Time: 6 minutes
Summary
  • The turn signals lights are amber-colored lights on the side of your vehicle’s front and rear ends.
  • It might be time to get your turn signals checked out if your turn signal works erratically, appears dim, or if your hazard lights don’t work at all.
  • Turn signal light failure may be caused by a blown fuse, a burned-out light bulb, or a clogged light bulb socket.

Always remember that you’re not alone on the road and that other drivers also populate the streets and highways, each with their own destinations and schedules. To avoid accidents and minimize delay, you must communicate with them clearly and succinctly.

Your vehicle comes with a plethora of signaling devices to let other drivers know what you plan to do. Of particular note are the turn signal lights that indicate which direction you intend to go. If one or more of these lights act erratically, they can compromise your road safety. Familiarize yourself with bad turn signal light symptoms and replace the faulty parts as soon as possible.

What Is the Turn Signal Light?

Turn signal lights are external automotive lights on the sides of your vehicle’s front and rear ends. They are usually colored amber, but some are colored red depending on the country’s regulations.

Some turn signals use the same bulb as the stop lamps, while others may have all the stop lights (including the high mount “CHMSL” light simply wired together, with separate bulbs for turn signals). Some of these systems with dedicated turn signals that aren’t integrated with the stop lamps will have amber turn signals. The turn signals are either flashed on and off by an electronic module or a flasher unit, depending on the platform.

When you’re wiring up a trailer tow kit on a vehicle with this setup, you need a special adapter because the lights on trailers will have stop lamps and turn signals sharing the same bulb.

Some vehicle models will also have additional turn signal lights mounted on their side fenders, side mirrors, or both. These secondary warning lights are called repeaters, and they turn on or off together with the turn signal lights.

On a vehicle with side marker lamps on the fenders, the small lamps will flash along with the turn signal on the same side of the vehicle, but will alternate with the turn signals whenever the headlights or park lamps are on. In other words, when the park lights are illuminated, the side marker lamps will be on all the time but they’ll turn off each time the turn signal light illuminates. If the park lights are off, the side marker lamps will flash “on” each time the adjacent turn signal is illuminated.

This image shows various kinds of bulbs. The bulb on the far left with the plastic base can be plugged in either way and still works the same. However, because of the nature of the terminal contacts, these bulbs may cease to function even though the filaments haven’t failed. | Image Source: Richard McCuistian

On a vehicle with side marker lamps on the fenders, the small lamps will flash along with the turn signal on the same side of the vehicle, but will alternate with the turn signals whenever the headlights or park lamps are on. In other words, when the park lights are illuminated, the side marker lamps will be on all the time but they’ll turn off each time the turn signal light illuminates. If the park lights are off, the side marker lamps will flash “on” each time the adjacent turn signal is illuminated.

Richard McCuistian, ASE Certified Master Automobile Technician

On the other filament style bulbs, you can either see a broken filament through the glass or you can thump the bulb and the filament will jiggle so you can see the bulb has failed. The LED bulb is supposed to last longer but it may not. LED bulbs can fail very early in the life of the car and can still consume power even if the bulb isn’t illuminated.

Newer cars (except for some European platforms) have the lights on both ends of the vehicle designed so they’re visible from the front and the side, which eliminates the need for side marker lamps.

Bad Turn Signal Light Symptoms

Turn signal lights may need replacement at least once during your vehicle’s expected service life. Even turn signal lights fitted with long-lasting LED bulbs are not immune to premature failure. However, note that turn signal lights sometimes last the life of the vehicle.

These common symptoms will warn you about a right or left rear turn indicator failure:

Turn Signal Lights Work Erratically

When you engage the turn signal lever, the signal lights are supposed to immediately illuminate. Furthermore, the turn signal lights should blink steadily and regularly. Last but not least, the lights should turn themselves off automatically after making a turn. This is typically built into the turn signal switch and interacts with a small plastic bump or boss that moves with the steering wheel.

If the turn signal lights fail to accomplish one or more of the above tasks, there’s a good chance that something has gone wrong.

Newer turn signal systems will flash twice as fast on a side where one of the bulbs is burned out.

Dim Turn Signal Lights

There’s a chance that a worn-out turn signal light might not immediately stop working. Instead, the old bulb might shine less brightly.

It’s much harder to spot a dim turn signal light, especially during the day. Other drivers might even think the light isn’t running, only to get surprised when your vehicle turns without warning.

In most cases, you shouldn’t wait for a dim light to turn into right or left rear turn indicator failure. Replace the faulty part at the earliest possible time.

Hazard Lights Don’t Work

Hazard lights use the left and right signal lights and make both blink at the same time.

Unfortunately, a problem that affects the turn signal lights will also apply to the hazard lights. Whether the issue involves dim light bulbs, incorrect operation, or something else, the warning lights will stop working as intended.

Other Drivers React the Wrong Way to the Turn Signal Lights

Did you engage the right turn signal light before turning the steering wheel, only for the other drivers to either ignore your signal or respond incorrectly to your turn? The warning light might have stopped working without you noticing it.

Since the turn signal lights are externally mounted, you usually cannot see them from within your vehicle. You might not realize the problem until you step out to look at the warning lights.

What Can Cause a Turn Signal Light to Fail?

Some of the possible causes of a bad turn signal light are:

If you plan to replace the turn signal light yourself, run a thorough test to identify the source of the problem. Otherwise, you will be better off bringing your vehicle to a trusted auto service center.

More About the Turn Signal Light

Turn signal lights have several alternate names. The most common term is blinkers, which refers to how these lights blink on and off when used. Other names include direction indicator lights, directional signals, directionals, and indicators.

A faulty turn signal switch- can cause your turn signal to fail.

What Does the Turn Signal Light Do?

Turn signal lights inform other drivers about your intention to make a right or left turn. They catch people’s attention through a combination of bright illumination and blinking patterns.

Usually, you control the turn signal light through the turn signal lever. Usually found jutting from the steering wheel’s left side, the lever allows you to operate it with one hand while your other hand stays on the steering wheel.

In left-hand drive vehicles, you move the turn signal lever upward to indicate a right turn and shift the lever down to indicate a left turn.

The instrument cluster will have two green arrow-shaped indicator lights. One of the arrows points left while the other points right. The right or left indicator lights illuminate when you turn on the corresponding signal lights.

Once you complete the turn or finish changing lanes, the turn signal lever will return to its neutral position. Then the warning lights will turn off. Some older vehicles might require you to disengage the turn signal lights.

How Much Does a Replacement Turn Signal Light Cost?

Planning to replace a faulty turn signal light? Prepare to pay anywhere between $10 and $860 for a replacement part. Keep in mind that various factors like the product’s brand and your vehicle’s details can drive the turn signal light’s price tag up or down.

Finding a New Turn Signal Light for Your Vehicle

You shouldn’t drive your vehicle if its turn signal lights are malfunctioning. CarParts.com carries a wide selection of replacement turning signal lights, so finding the right one for your ride should be easy.

Why waste time driving from one store to another when you can order parts from the comfort of your own home? Visit our website, use our vehicle selector to filter out incompatible parts, and place your order with just a few clicks. It’s that easy!

We know the importance of having a functioning turn signal light on the road. That’s why we only source our products from the biggest names in the industry. Our selection of turn signal lights was handpicked by our team of industry veterans to ensure they offer long-lasting illumination.

The good news is that all parts in our catalog come with a low-price guarantee. You don’t have to break the bank just to replace your busted automotive lights.

Check out our catalog, and order your new turn signal lights today!

About The Authors
Reviewed By Richard McCuistian, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

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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Published by
CarParts.com Research Team and Richard McCuistian, ASE Certified Master Automobile Technician