Checking The Brake Light Circuit

How To Check The Brake Light Circuit?

The brake light circuit in most vehicles is straightforward. You don’t have to be a professional to diagnose errors and make necessary repairs. The circuit consists of a fuse, a brake light switch, the vehicle’s lamps, and a connecting wire to join them together. The brake light circuit is connected in a parallel manner. If one becomes busted, the rest will work well. It is thus vital to understand on how to check the brake light circuit.

Knowing the signs to look out for and the potential causes of the problem will help you fix it. It will show the extent of the damage, and you can thus get the best value for your money for the repairs or replacements you make. Here, you will learn why your car lights are not working and correct the problems.

Why are the Brake Lights not Working?

Car lights, unlike many components on your vehicle, are easy to identify when they malfunction. If they don’t light or are dim, you know they have problems. There are various reasons for your car lights to stop working. These include;

  • The fuse is blown-out: The fuse is used to break the electric current in case it is too much. It prevents the brake light lamp from getting burnt, and thus, you will only have to replace the fuse. It is a simple and money-saving aspect of the setup.
  • The lamps are blown out: The brake light lamps will interfere with the brake light circuit if they are damaged. A replacement should be made for it to work well.
  • The brake light switch is worn out: As we will see, the brake light is an important part of this connection. You should thus evaluate it carefully when checking the brake light circuit and identifying why the lights aren’t working.
  • The connection wires are connected to the wrong points: This will result in either the brake lights failing to go off or failing to turn on depending on the error. It will also occur when the cables are cut, and thus no power is transmitted.

Checking Various Components on the Brake Light Circuit

Various components make the brake light circuit. You will thus have to test all components independently to identify which is causing these problems. It is a simple connection, and you can do it without professional help. These are the various components you can test;

#1. Performing visual checks

Performing a visual check is a simple way to identify the causes of the problems. All you need is a weight strong enough to press down on the brake lever. Ensure the vehicle is turned on before starting the test. Now, place the weight on the brake lever and look around the vehicle.

Identify any lights that aren’t turned on. If the problem is on only one of the lights, it could be a busted fuse to the bulb or the bulb itself. You might, however, have a connection problem or a malfunctioned brake light switch that will need repairs or replacement.

#2. Checking The Fuse

The fuse cuts off power transmission if your alternator releases too much power to the various components such as the lights. Firstly, locate the power distribution centre on your vehicle, where the fuses are located. You can find them using the vehicle manufacturer’s manual. In many vehicles, it is located under the bonnet.

Remove the lid on the power distribution centre and look at the status of the fuse. You can also remove it from its compartment for better evaluation. Now, look into the fuse element to identify if it is burnt or damaged. You can also use your multimeter to test the fuse for certainty before purchasing a replacement.

Replace the fuse by getting the right model for your brake light circuit. You can tell this by identifying the model number. Replace it into the slot, and it should fit in perfectly. You can now test the lights to see if the problem is fixed.

#3. Checking the brake light switch

The brake light switch is an important part of this setup. When the driver presses on the brake pads, it relays signals to the control box, thus initiating the stop. It will also send signals to the brake lights to turn on and thus indicate the vehicle is coming to a stop. Checking the brake light circuit as soon as it develops challenges is thus quite important.

Firstly, find the brake light switch location beneath the brake pedal. Vehicles with active cruise control will have two brake light switches, and you must inspect them individually. You can now use a test light once their positions have been identified. Secondly, connect the test light to the battery for power and connect its terminals to the brake light circuit individually.

If the test light lights come on, it means the switch is working well. If it remains off, however, it shows there is a short circuit in one of the components connected to this terminal being tested. You can thus choose to repair or replace it depending on the state of the damage.

#4. Checking the Cable Connection

The cables in the light circuit might wear out after some time due to the harsh elements. You will thus have problems with the lights in case they break. Testing the cables for proper integrity is simple as all you have to do is look along with them. Identify any areas with breaks and fix them with insulating tape. Ensure the terminals of the brake cables are connected to the right areas. It will, however, only arise if you have opened up the brake light circuit before.


Checking the brake light circuit ensures you always have a properly working installation. It will prevent accidents and ensure you can drive legally. Also, take a look at this Akebono and Performance comparison. The light components are simple to handle, and you won’t need a technician. This is how one learns to identify the errors and fix them.