Turn Signal Bulb Sizes

Turn Signal Lamp Bulbs: What You Need to Know in 2022

The turn signal more order and safety on the streets. A little bit of history: In the 1920s, to avoid traffic chaos, it became necessary for drivers to use certain signals to indicate a driving direction. In the beginning, a change in the direction of travel was shown by holding the arm out of the vehicle in the direction in which the driver intended to steer.

Turning left might have been easy, but stretching your arm visibly to the right was a difficult task. For this reason, the first indicator arms were soon developed. This was a metal rod that folds out of the body and shows the planned direction of travel.  

The turn signals we know today - commonly referred to as blinkers - were introduced in 1961 and became mandatory. Since then, yellow flashing light has indicated the intended change of direction. But what bulb can you use for the turn signal? Which colors are allowed? Our guide will tell you.

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Why should you use a turn signal?

An activated turn signal indicates a change in direction of travel. This is a light that flashes briefly at regular intervals on the right or left of the vehicle. The turn signal must be used in good time when:

  • Making a turn
  • Overtaking or changing lanes
  • Exiting a roundabout
  • Avoiding an obstacle
  • Pulling onto the road from the side of the road or property.

Turn lights are used as hazard warning lights that must be activated when a vehicle has broken down, is being towed away, or to warn of danger such as accidents or traffic jams.

Many drivers prefer not to turn on the turn signal, especially when there is little traffic. But according to the rules, if you want to turn, you have to activate the turn signal first. It doesn't matter whether you are all alone on the road or in hectic city traffic. 

You must also turn lights even if the direction of travel is prescribed, for example by a driving direction requirement, such as a blue sign with an arrow pointing to the left or right. In any case, you must not forget the turn signal.

Technical requirements to turn signal lamps

It is not only the operation of the direction indicator that is regulated by law – but it must also meet certain requirements. Among other things, it applies that both cars and their trailers must be equipped with turn signal lamps. Here are other things to keep in mind:

  • After switching on, the direction indicators must flash between light and dark at a frequency of 1.5 Hz ± 0.5 Hz (90 pulses ± 30 pulses per minute) and in the same phase on the same side of the vehicle – with the exception of motorcycles with AC lighting systems.
  • Turn signal lamps must be installed in such a way that all road users who need to see them can see them clearly.
  • The driver must be able to see whether his turn signal is working even when he is in the car. A control lamp is usually attached for this purpose.
  • Only flashing amber lights are permitted.
  • Cars and trucks must have turn signals both at the front and at the rear.

Types of turn signal lamps

LED side indicators are very popular in modern cars. Older vehicles usually have halogen indicators. In modern cars, on the other hand, LED lights are installed. These have special advantages. They consume less electricity, are more efficient, and are practically maintenance-free - they usually last for the entire life of the car. LED fog light lamps also score with a particularly high luminosity.

Another point makes the hearts of design lovers beat faster. LEDs are particularly flat and small. This means that they can be installed flexibly, which in turn gives car manufacturers more variation options both in the arrangement and the shape of the indicators. A pioneer of dynamic LED turn signals, also known as running light or intermittent turn signals, is Audi. Such a direction indicator has a wiping effect as various LED blocks are switched on one after the other, creating a dynamic display. However, certain rules must be observed with the turn signal running light:

  • The full luminosity of the LED running light indicator must be reached after 0.2 seconds.
  • The indicator must always run from the inside to the outside, i.e. in the direction of travel.
  • If the indicator warns of emergency braking, it must not be dynamic.

How do you know if the turn signal on the car is broken?

As already mentioned, a driver must be able to tell while driving whether his turn signal is actually working. The indicator light on the turn signal helps him with this. But how does that work? The circuit that is decisive for the flashing light is designed as a function of the load. If a bulb is defective, the load on the flasher unit is lower. This ensures that the indicator flashes faster - and the driver hears and sees that in the car.

Turn signal defective? You can tell by the fact that it flashes faster. And what about LED indicators? These can also flash too quickly. This can happen, for example, when an old vehicle is converted to new technology. 

Normal indicators have 21 watts, but new LED lights only have two watts. Therefore, the LED turn signal needs a resistor. This can prevent the power on the indicator from being too high. If this is forgotten, the direction indicator will flash faster. Instead of such a resistor, a load-independent relay can also be installed.


Turn signal lamps are one of the most important components of the vehicle safety system. LED turn signal lamps are very popular but there are legal regulations when it comes to their light and luminosity. You can install dynamic LED indicators to modify the appearance of your vehicle but certain rules must be followed. 


Are additional turn signals allowed?

Sometimes, turn signal lamps are attached to the rear of the roof and serve as additional turn signals. Can you retrofit such roof indicators? In principle, this is permitted if the flashing light for the car meets the legal requirements. A specialist workshop can advise you on this.

Note: It must be possible to see inside the vehicle whether the turn signal is working.

What colors of turn signal lamps are allowed?

As a rule, the color should be amber (yellow-orange). Many auto tuners like the look of a red turn signal, but it is not allowed. This color is not approved for indicators. Sometimes this violation may result in the invalidation of the vehicle's operating license or at least a fine. 

An exception applies to imported vehicles that were registered before 1970. There, red turn signals are allowed on the back of the vehicle if they are original.

Which bulb is the turn signal?

There are two filaments in each light bulb. One is for your brake light and one is for your turn signal.

How much is it to replace a turn signal bulb?

If someone comes in and they're not a regular customer, we'd probably charge $35 or $40. The bulb itself probably is five or six bucks, and it's a 10-minute job for someone who's done it a thousand times.

Can I change my own turn signal bulb?

Changing out a turn signal bulb is quick and easy. It simply involves removing the burnt light bulb and replacing it with a new one. Replacement bulbs can be purchased at automotive stores or through your local dealership's service department.

How many bulbs are in a turn signal?

The Basics: Turn Signal Bulb Overview

Most turn signal lighting systems include four separate bulbs: front left, front right, rear left, and rear right turn signals.

What is turn signal switch?

What is a Turn Signal Switch? Also known as blinker switch, turn signal lever, or turn signal arm, the turn signal switch is a lever that's usually mounted on the steering column. Pressing down on it engages the left signal while pushing it up activates the right signal.

Does O'Reilly change turn signals?

Our Parts Professionals will install wiper blades and replacement bulbs free of charge (with purchase of wiper blades or bulbs). Whether you've bought front or rear wipers (or both), headlights or tail lights, we'd be happy to install them for you. Restrictions apply. See your local store for details.

How long should a turn signal bulb last?

How to Know You Need a Turn Signal Bulb Replacement. Your owner's manual provides a guide on when to replace a signal bulb, though most last for about 4,000 hours.

How much do blinkers cost?

According to the video, every time you use your turn signal in the U.S., it costs $0.00004. Add that up over the amount of time you signal a year, and you get around $0.30.

Do turn signals have to be amber?

Most cars in the U.S. have red turn signals, while you often see amber ones in other countries. The U.S. allows amber turn signals, but doesn't require them.

Are front and rear turn signals the same bulb?

Typically, the rear turn signal bulb is located in the tail light housing; it is simply a matter of exchanging bulbs. The front, although it uses the same mounting method, maybe be more difficult to gain access to the front housing. In either case, the bulbs are cheap and easy to get.

Why is my blinker blinking fast?

A bad bulb is by far the most common reason that a signal blinks faster. This is because a bad bulb alters the resistance in a circuit, sending a different current through the blinker. To figure out if this is the issue, test all signal lights to see if any bulbs are visibly out.

Are front turn signal lamps red?

Registered. In most states the front signal lights must be between a shade of white or amber. Rear signals can be between a shade of amber or red.

How do you change a rear turn signal bulb?

Replace Your Car's Burnt-Out Bulbs in 4 Simple Steps

  • Unscrew the Taillight Housing. Remove the tail light housing screws. ...
  • Pull Out the Light Housing. Tail lamp assembly coming out. ...
  • Unscrew the Bulb Holder. A quick turn and you have access to the bulb. ...
  • Pull Out the Old Bulb. Remove the old bulb and replace.
  • How do you change a left turn signal bulb?

    How is Turn Signal Bulb Replacement Done?

  • Verify that the turn signal bulb does not flash.
  • Prepare to test the turn signals.
  • If the bulb found faulty, replace the front turn signal bulb.
  • Prepare to remove the old turn signal bulb.
  • Remove the electrical connector and old bulb.
  • Reassemble the turn signal.
  • How do you tell if a car light bulb is burnt out?

    The trick is to shake the bulb lightly once the bulb has cooled off completely. If you hear something rattling around, the filament has broken, and you know the bulb has burnt out or is otherwise damaged. Low wattage bulbs may produce a very unpleasant smell if they have burnt out.

    What are the signs of a bad turn signal switch?

    Symptoms of a Bad or Failing Turn Signal Switch

    • Turn signal indicator continues to blink when the steering wheel returns to the center.
    • Turn signal lights don't continue flashing unless turn signal lever is held down.
    • Left or right turn signals or the Hazard Warning Light not working properly.

    Where is the turn signal switch?

    A car sends signals through the turn signal lights located at the four corners of your vehicle. These lights are activated by the turn signal switch located inside the car. This switch is activated by a lever that's installed right in the steering wheel or in a separate assembly near the steering column.

    Can turn signal switch affect brake lights?

    A bad turn-signal switch may interrupt the brake light circuit when it should not. A broken wire to or from the switch may also cause the lower brake-lights not to work. The third brake light does not flash with turn signals. This is why a bad turn signal switch will not affect it.

    When should I replace my turn signal bulbs?

    Fixing a burned-out turn signal bulb is a safety concern as well as a monetary one. When a turn signal bulb gets burned out, it's important to replace it as quickly as possible. If you drive with a burned-out turn signal bulb, you are at risk for a possible ticket and heavy fines.

    How often should you check your turn signals?

    Full replacement of the turn signal fluid should be done about every 20,000 miles, or at every third oil change, whichever interval is less frequent.

    Why do my hazards work but not my turn signals?

    The hazard or emergency lights may share the same circuit with the turn signal circuit. When your hazard lights don't illuminate but the turn signals work, usually you are dealing with a faulty hazard-lights flasher. However, if the flasher unit is working fine, check the fuse.

    Why does my turn signal not work sometimes?

    One Side of Turn Signal Won't Work

    You might be working with a bad wire, a bad flasher relay, bad bulbs, a faulty switch, or a faulty connector between the signal switch and the flasher unit. First, check to make sure the bulbs are in working condition. No damaged filaments or darkened zones.

    Why does my turn signal stay on after I turn?

    The problem is the cancellation spring located in the turn signal arm. This spring makes contact with the high spots in the column when the steering wheel turns. These high spots hit the spring and cause it to return to the neutral position.

    Why do LED bulbs fail so often?

    Unlike incandescent light bulbs, LEDs don't produce light using heat. This is part of what makes them so energy efficient. The downside is that their components can be sensitive to overheating, which can cause them to burn out prematurely.

    What does it mean when a light bulb turns black?

    Why does a light bulb turn black? Over the life of an incandescent light bulb, the filament begins to deteriorate and the particles will settle on the inside of the glass. In return the bulb will take on a grayish appearance and a slight decrease in light output may occur.

    Do light bulbs flicker when burning out?

    If the actual LED burns out (somewhat unlikely) it will get dimmer and off-color. The traffic lights that 'burn out' are more often the power controllers / diode packs than the actual LEDs going dead. Flickering would be caused by the power controller, which would be built in to most consumer LEDs.

    How much is it to replace a tail light?

    A new tail light switch, accounting for labor, will cost from $70 to $100. The plastic and colored lens over on top is a bit more pricey. Depending on the make and model of your car, a replacement tail light lens will leave you lighter by between $100, and upwards of $750.