Why Do My Turn Signals Blink Fast With LED Lights?

Suppose you are thinking about upgrading your existing old-style filament or halogen turn signals for something brighter. In that case, you’ll find that LED turn signal bulbs are now relatively inexpensive and let you upgrade at a low cost.

However, while fitting LED turn signal bulbs may be a great idea, they come with their own set of challenges.

The fast blinking of LED turn signals is called hyper-flashing. It occurs due to the incompatibility between old car electronics and new LED technology. The hyper-flashing can be easily fixed by installing an additional resistor or relay.

Now let’s dig deeper into the hyper-flashing issue and learn about:

  • Why do so few cars have LEDs installed by default?
  • What causes the hyper-flashing
  • What can you do to fix that

Without further ado, let’s get to it.

Why Don’t More Manufacturers Use LEDs In Their Turn Signals?

Manufacturers have been prompt in replacing HID and halogen bulbs in vehicle headlights with more efficient LED bulbs.

However, they have been pretty slow when doing the same with turn signal (indicator) bulbs.

It seems a little strange when you think LED bulbs are cheaper and take up less space if you ask me.

Currently, only selected BMW, Mercedes Benz, and Honda come with LED indicator bulbs. However, BMW only comes with rear LED indicators.

Hopefully, we start seeing more manufacturers installing bright LED lights onto their vehicles.

Since LED turn signals flash, they showcase the instant on/off benefit of LEDs and can update any car’s aesthetic.

In-fact some dual-filament bulbs can even “switchback” between white and amber LEDs, not only giving an ultra-modern appearance, but they also look fantastic and get the attention of other drivers.

But, unfortunately, looking awesome doesn’t always cut it with the automotive industry.

You see, many low-quality LEDs can suffer from brittle solder joints that can easily break if used in high-vibration applications such as vehicles with stiff suspension, which puts many manufacturers off.

Also, if not addressed, you get what is called “hyper flashing,” which is the reason why your aftermarket LED turn signals to blink faster than your stock incandescent bulbs did – but don’t panic.

As you will see after that article, it will be an easy fix.

Read more: Do LED Headlights Blind Approaching Drivers?

Why Do LED Turn Lights Hyper Flash?

Let’s see what causes the indicators to hyper flash on older vehicles.

This phenomenon arises as a result of one or two things.

Firstly, it can happen when the LED bulb has been installed into a turn signal circuit designed to work with older incandescent bulbs and not the more modern LEDs.

As a result, the CANBus system returns the error and causes the hyper flashing.

In other cases, it occurs because the installed LED bulb creates a smaller load on the circuit and draws very little power.

The turn signal relay in the vehicle’s electronic management system thinks it is a blown incandescent.

It then flashes fast to let you know that one of your bulbs is burnt out, which, in reality, is not quite right.

Also read: Why Do My LED DRLs Flicker?

How To Fix Hyper Flashing Turn Lights

To fix ‘Hyper-flashing’ and to return your turn signals to a more regular speed, there are several strategies you can adopt to fix the issue.

  • Fitting or replacing an existing turn signal relay
  • Installing load resistors to mimic the original light bulb load
  • Using LEDs with built-in decoder and resistor

While these fixes are all pretty straightforward and can be easily achieved, they all come with their own set of individual challenges and considerations. So let’s have a closer look.

Installing LED Flasher Relay

Installing an LED flasher module specifically designed for LED bulbs is the easiest method for fixing hyper flashing.

These modules are economically priced and there are various brands to choose from including those from Dewhel (Amazon).

They are simple enough to install. In most cases, the flasher units are little circular or square boxes with metal prongs sticking out one side that plugs into where your stock flasher went.

These types of LED flashers function with both LED and incandescent bulbs, so even if you have new LED turn signals in the back and incandescent bulbs still in the front, you can use this type of LED flasher modules with no problems.

Although this is one of the easiest ways of fixing hyper flashing, you need to remember that the turn signal is often controlled by the electronics management system with today’s cars.

So if that is the case, the only way of adding an LED turn signal relay is to by-pass the existing control module.

In other words, you need to remove the existing turn signal inputs and outputs from the control module and connect them directly to the LED turn signal relay – which might not always be a good idea and return you extra errors.

Before you order your flasher module, it is important to compare the pin diagram of the stock flasher with the pin diagram of the flashers you are looking to buy.

Related: Can LED Bulbs Be Used In Tail Lights?

Installing LED Load Resistors

Unlike the plug-and-play LED flasher module that we spoke about earlier, the load resistor does need some wiring as part of the installation.

But, a typical 12-volt 50-watt load resistor, say something like the Huiqados (Amazon) 7443,7444 NA T10 LED load resistor, does come with everything you require to install them.

The LED bulb blinking can be slowed down to a regular rate by installing a load resistor, so mimicking the original light bulb load.

These resistors need to be installed in parallel (tied to positive and negative) for each LED bulb front and back.

The fitting process is the same for any vehicle, and you can buy vehicle specific resistor kits.

Remember, installing the load resistors, makes sure to mount them onto a metal surface away from any plastic trim. They do create decent amounts of heat when the signals are left on for extended periods.

Using Resistors Does Not Defeat The Purpose

On the subject of fitting load resistors, some would suggest that you’re actually defeating the purpose by fitting load resistors, as you are increasing the energy consumption.

The response to this point would be that the difference in energy consumption when turn signal resistors are fitted is so minuscule that it is irrelevant.

Think about it. Your engine doesn’t work any harder to run halogen turn signals than it does to run LEDs. Remember, the idea behind installing LED bulbs is for the increased brightness and visibility.

Not to mention the longer life expectancy of LED bulbs. Even if there was any large increase in energy consumption, it would be well worth it in the long term.

Get High Quality LED Turn Lights

When it comes to buying LED turn signal bulbs, you may notice that many of the market products look similar and advertise many of the same features.

Which is true for the most part.

The majority of LED bulbs are alike, the main difference being which LED chips they use, and some LEDs feature aluminum housings for better heat dissipation and performance.

You will also find that some LEDs come with projector-style lenses that deliver more than triple the brightness of a factory-installed halogen turn signal light.

I would recommend you to check out Lastfit, where you’ll find their CANBUS 7443/7444 LED bulbs.

These are designed to be used without load resistors and are fitted with an anti flickering mechanism.

Final Words

There is no doubt that as vehicle manufacturers continue to search for innovative design ideas and reduce core material costs, the use of LED lighting throughout the car will increase.

Okay, so now, when you know how to deal with hyper flashing by installing either a flasher module or individual load resistors, would you install LED indicators on your car?

Share your thoughts below.

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