• Turn signal
• Faulty
• How to check
• What to do
• Diagnosis
• Repair
• Mechanic
• Car
• Vehicle
• Auto

Imagine needing to head somewhere but your turn signals won’t work. This can really be bothersome especially if you’re in a hurry. 

Functioning turn signals is crucial even if you just need to do a quick drive to a nearby friend or grocery store. It’s the only way to let others know that you’re turning the car. 

Most importantly, it is required by law.

Oftentimes you’ll notice that your signal is working okay, but sometimes it won’t. You might have found yourself telling your significant other they don’t work but they work for them. 

The case of “my turn signals work sometimes” is a common occurrence but nothing to stress about.; and before you think of going to your mechanic to have it fixed, check if you can determine the cause of the issue and try to do a quick fix yourself.

Here are some reasons why it won’t work and how to fix it. 

What Is A Turn Signal?

The turn signal is a very important part of the vehicle. Most people tend to take this lightly that’s why they don’t utilize the turn signals when they’re just within the neighborhood. They think they are too familiar with the area and don’t feel the need to warn others of their impending turn or move. However, some accidents and road rage are caused by failing to signal. 

The four corners of a vehicle are equipped with turn signal lights. The turn signals on the dashboard appear as green arrows and would flash facing the direction of your intended turn. 

The turn signal lever is usually located at the left side of the steering wheel. If you shift the lever down, it means you’re turning left. Shifting it up means you’re turning right. After a turn or lane change, the turn signal should automatically turn off. If it won’t, then you need to turn it off manually.

Causes and Fixes

Faulty or Blown Bulbs

Turn signal light bulbs should last for quite a while but it would still depend on how often you drive and use your turn signals. 

You need to check first if the bulbs are working. If the turn signals flicker before it stopped working, then you might just need to replace the bulbs. You can check your user manual to find the bulbs. It could be in your trunk or hood depending if it’s your rear or front signal. 

When you’ve found the bulb, take it out and shake it. If there's a rattle sound, then it’s time to replace it. Same thing if there are signs of scorch marks. 

Faulty Turn Signal Switch  

The turn signal switch is the lever that you use to turn the signal on and off. If it doesn’t work, it could be a switch or a wiring problem.

Troubleshooting the turn signal switch can be difficult and time consuming so it’s best to consult your user manual. 

• First step is to disable the system for airbags.
• Remove the top or bottom shroud at the back of the steering wheel.
• There would be wires connected to the turn signal lever and you can check your user manual for the wires control.
• Turn on the right signal.
• Back probe the wire for the right turn signal. The test light should flash
• Then, back probe the wire for the left turn signal.  There is a short in one of the wires if your test light flashes. 
• Do the same with the left turn signal. If the tests show a short in the turn signal switch then it’s time to replace the lever.

Oxidized or Dirty Socket Bulbs

Oxidation or rust affects almost all parts of your car at some point; and the turn signal is not spared from it. That’s why it’s recommended to check any electrical connection for any dirt or rust. The build up between the bulb and socket can disrupt the power connection. If this happens, buying an electrical cleaner and compressed air from the auto parts store can fix the problem. 

• First thing to do is to disconnect your vehicle's battery.
• Spray the electrical cleaner into the socker and let it sit for 3-5 minutes or as instructed.
• Spray the compressed air into the socket
• Then you can use or apply dielectric grease on the bottom and around the bulb. This can prevent rust or dirt build up. 

Blown Fuse

A fuse in your car may blow because of too many signals going on at a time. If the heat and energy level gets too high, it can also melt. Once this happens, you’ll need to replace it. 

To locate the fuse, you can use your user manual for vehicle-specific locations.  

To test a fuse, use a test light and probe both the ground and power connections. The fuse is working fine if it lights up.  

You can also pull the fuse and look through to see the “U” shaped metal piece, if you don’t have a test light. You need a new fuse if that is broken. 

Good thing that fuses are cheap and easily available at any auto parts store. 

Broken Flasher Module 

A flasher module or flasher relay is part of your turn signal system. It sends the power from the battery to your turn signal system. The power won’t reach your turn signal once your flasher module is broken. Since your turn signal system is connected to a bunch of other systems, they may all blow or get broken at the same time. 

This flasher module is connected to your fuse through a piece of lead so it will not work if the lead gets damaged. 

It won’t be easy to test a flasher so it’s recommended to replace it instead. However, it's still always better to take this to your trusted mechanic to get it replaced or fixed. 

Consult Your Manual

It can be easy to explain the issues that we get with turn signals but the troubleshooting part can be difficult and time consuming. Make sure to always consult your service manual to avoid bigger problems in the future.   

If you are not confident enough or comfortable doing this yourself, seek assistance from your trusted mechanic.