How to test a turn signal relay when you find it’s malfunctioning?
This situation is common in most vehicles. Sometimes, minor electrical problems can cause this system to fail.
In fact, it’s not difficult to identify the cause as well as solutions, e.g. replacing the relay at home. And right now, you can find the answer in the next section.
How To Test A Turn Signal Relay

To examine the turn signal relay, you should check the connection, check the random fuse, swap the relay, take a volt test, and check for resistance.
It may take you about 10 minutes to learn the entire guideline.
Start with the first step now!
Check The Connection
Like when you test the AC clutch relay, when you want to test the flasher relay for a turn signal, checking its connection is the first step.
Problems with connection are not uncommon. Sometimes, a small mistake in the installation process also leads to a malfunctioning part, or even both turn signals not to work.
Make sure its connection is fine and working properly. If you detect issues such as short circuits, faulty connections, etc., fix them immediately.
Check Random Fuses
How to test a flasher relay? Use a circuit tester between the earth and the terminal marked B on the flasher unit to test it. Start the car’s engine.
The bulb should illuminate if the supply side of the device is functional. Suppose it doesn’t; check for a wiring tangle between the appliance and the fuse box.
Swap The Signal Flasher Relay
How to replace a turn signal relay?
The first thing many car owners notice when they glance at this part is that several relays in that location all have the same appearance. They are almost always identical.
When the part numbers are identical, double-check them, and then switch the relays. It is the issue if it “migrates” to another component of your car.
This the simplest and nearly surefire method for determining whether it is malfunctioning.
The Volt Test
Even though this method of testing a relay isn’t perfect, it manages to identify 95% of the issues. How to test a flasher relay using the volt test?
Prepare a six-volt battery and take the turn signal relay out of your car to complete the task. Connect the two terminals to the six-volt battery, then wait for a clicking sound.
There’s a strong likelihood this part is operational if you hear a click. But if it doesn’t click over, it must be replaced.
Check For Resistance
How to test a turn signal flasher? Connect your multimeter to the appropriate two terminals and set it up to check for resistance.
A relay that is working properly should have resistance ranging from 50 to 120 ohms. It’s time for a new one if the reading is outside of this range.
Remember that the relay is probably trapped closed if there is little resistance, in which case you also need a turn signal relay replacement!
Common Symptoms Of Bad Turn Signal Relay
It Stops Working
One of the most common symptoms of a bad turn signal relay is not working.
When you hit the turn signal lever or danger light button, the lights may fail or not work if the flasher malfunctions or has any internal problems.
While this won’t always affect how well the engine performs, it will prevent the warning lights and, more crucially, the turn signal lights from working, which could compromise safety.
To prevent the bad flasher relay symptoms, you should verify your MOT’s status and resolve the issue. Another easy explanation for this could be a blown bulb.
It Won’t Turn Off
Another typical bad turn signal relay symptom is illuminated warning or indicator lamps. If it has a short circuit when the hazard flasher or indicator is activated, the lights could remain on rather than flashing.
But they won’t be able to signal a turn or alert other drivers in an emergency.
Having your car properly inspected by a professional is crucial because electrical defects might cause symptoms similar to other problems.
Light Malfunction
The bad turn signal relay symptoms include additional lights (headlights, running lights, etc.) that don’t work with your hazards. Sometimes, just one headlight might turn on and off.
Certain automobiles will have a problem if the flasher fails since other lights are wired through or with the flasher.
Even though a broken turn signal relay typically does not impair the car’s ability to drive, they can harm visibility and safety.
Flasher relays are simple parts. Still, because electrical systems are so complex, diagnosing them can sometimes be challenging.
FAQs
Where Is The Turn Signal Relay Located?
It will most likely be located within the fuse or the function box with your other ones. The relay location is depending on the sort of car you drive.
On the fuse box cover of certain vehicles, there is a guide that explains which relay accomplishes what; in other vehicles, you must search through the owner’s manual to obtain that information.
How Much Does It Cost To Replace The Faulty Turn Signal Relay?
When you notice the symptoms of a bad flasher relay and can’t find any way to fix it, it’s time to replace this part.
It may cost you $60 to $120 to fix the malfunctioning turn signal relay if you take it to a qualified mechanic, including labor costs. And this amount is quite expensive.
However, you can save an amount by doing it yourself since it is a simpler part to replace. You have to pay about $30 to $60 for parts.
You can frequently locate inexpensive third-party flasher relays on Amazon and eBay in the $15 price range. Spending a bit more will ensure that you have the right OEM replacement.
What Causes The Turn Signal Relay To Stop Working?
When a system shares connections and cables with the parking, warning, and braking light systems, a faulty turn signal relay might be difficult to identify.
Bulb sources, cables, connectors, emergency flasher units, fuses, and switches are typical sources of issues.
You can diagnose these defects with a test light and, occasionally, a digital multimeter (DMM).
Final Thoughts
You’ve got the guidelines for how to test a turn signal relay. It’s applicable for most car models unless your vehicle has a special design.
Finding a mechanic to repair this part is quite expensive, but you will save a lot if you replace it at home. So don’t skip the replacement guide; it will be helpful!