Replace a Flasher Unit

How To Test And Replace A Flasher Unit?

A turn signal flasher unit is a car component with the highest chance of troubleshooting. You can’t compromise on a flasher unit. Either they will work completely fine, or they won’t work at all. Figuring out the problem of why your flasher unit isn’t working and needs a replacement is easy. There are a couple of visible indications of why your turn signal flasher unit could have stopped working.

If it’s on without blinking or if it’s blinking, a lot of it’s not turning on at all. In these instances, it’s most likely your flasher unit needs a replacement. There are usually only two common causes why a turn signal flasher unit may stop working. It’s either if the bulb in it is dead or there’s a bad quality turn signal. Knowing how to test and replace a flasher unit is easy, and we will explain why.

Types of flasher unit

There are two different sorts of flasher units. One of them works with the help of a wire or a bimetallic strip. This strip contracts and expands when it gets in contact with the current heat. A relay of a transistorized circuit operates the other type of flasher unit. The type that has the strip is easier to test if it’s working as it makes a clicking sound. It makes the clicking sound if it’s working properly. You can use a test lamp or a circuit tester to check for faults.

 However, the other type does not make a sound, so you can’t check it with a circuit tester. The cause of a short circuit can also damage the transistorized type. You’ll have to check if all the other components from a transistorized type have any faults.

Replacing a flasher unit

The flasher unit would most likely be held on tight by a bracket fitted in with screws. It also can be fitted in a spring clip or plugged in the fuse box. It can also be seen just hanging at the backside of the instrument panel. Before you’re about to remove the wires, it’s advisable to remove them so you won’t be confused. If it’s a plug-in, you won’t have to worry about labeling anything. A two-terminal type won’t have a terminal for the instrument panel light. The instrument panel is connected to the switch.

Proceed to replace the unit. Remember that the type number of the unit that you have to replace with is on the cover. Your car’s electrical components are necessary for an easy and comfortable drive. Fitting a new voltage regulator can do wonders for your car, and you’ll notice some improvement.

Checking out faults

If the indicators are completely dead and aren’t doing anything, you’ve to check the fuse. When a fuse blows out, other components would also stop working that are in the same circuit. The manual or handbook of your car will come in handy. You can read it to know which components are there supposed to be in a circuit. A manual is useful if you forgot something about your car or you don’t know about something related to it. Not only a circuit but a battery and all the connections it leads to are always good to check on as well for the best electrical performance.

You’ve to fit a new fuse now. Unfortunately, if the fuse blows out, you’ll have to use a shorter fuse, simple as that. Check out the hazard warning and stalk switches if the newly fitted fuse is sound. Check out the flasher unit as well. Proceed to take out the stalk switch cover to check if the new unit works.

There are several places for the flasher unit to be placed at. It can either be under or behind the bonnet, plugged in the fuse box, or simply near. Check if all the connections and wires are alright.

How to test a flasher unit

A circuit tester can be used to test a common flasher unit. Use it between the terminal marked B between the earth and unit. Start the car put it in the ignition. The bulb will light up if the supply side of the unit is working perfectly.

However, unfortunately, if it doesn’t light up, you can check the break in the wiring between the fuse box and the unit. Check with the tester between the earth and terminal marked L if the tester has been lit. The lamp may flash and light up.

The fault is in the wiring or the switch if it works, and if it doesn’t, the whole flasher unit could be of bad quality hence the faults it has.

Hazard warning lamps

Hazard warning lamps are something new, and they come with every new car model. It’s for use when a car is at a fixed position and could be a risk for other nearby drivers that are going on the way. This type of switch operates by bypassing the normal switch. It uses the flasher unit to give signals to all the indicators of the same type.


A car is sort of like your baby, and it needs constant care to behave properly. It needs attention, or it can have trouble driving or with its other components. Cars when not in perfect condition or if there’s something that is broken with them, the troubles in driving can be not only annoying while driving but also very risky. 

It’s important to keep your car in tip-top condition by testing and replacing flasher units, changing tires, checking the radiator and engine. Make sure the engine has enough oil. All these things are very important if you love your car.