Tail Lights Not Working But Brake Lights Are

The brake lights of our car are one of the most essential of the vehicle. This group is in charge of signaling other drivers that we are slowing down. We can be involved in a rear-end accident if the brake lights are not activated.

You may have encountered situations like the tail lights not working, but brake lights are. There are a variety of reasons why brake lights can fail. Most often a bulb has blown, but when none of the brake lights work, one of two things has happened: either we’ve been too lazy and they’ve all blown, or there’s a problem with the electrical wiring.

Tail Lights Not Working But Brake Lights Are

Failure of the taillights and brake lights can have several causes.

1. Faulty Tail Light Bulb

If only one of the brake lights is not working, it is most likely due to a blown bulb in the vehicle. Typically, a 24V P21 bulb is used. The difficulty of replacing it with a new one varies greatly depending on the type and make of the vehicle, but in most cases, the procedures to follow are always the same.

We suggest that you disconnect the battery before starting the engine. Although it is not absolutely necessary, it is beneficial to be careful when electrical components are going to come into contact with other materials.

  • The first thing to do is to open the trunk to gain access to the rearview mirror lights. Nowadays, it is most common to have to remove the tail light, but it is also possible to simply access the bulb holder without having to remove any other part of the vehicle. The light is usually attached to the side of the vehicle and inside the trunk.
  • Remove the bulb holder regardless of whether you have to disassemble the light to do so. It is often held in place by a tab or screw.
  • Once the bulb holder is removed, remove the bulb in the same manner as you would a standard household light, turning it counterclockwise. Depending on the situation, it may be necessary to press it in to turn it. This is a method designed to improve its hold and ensure that it does not loosen during the running process.
  • Check to see if the bulb is actually blown or if it has loosened.
  • The metal contacts of the bulb holder may need to be cleaned, especially if the vehicle is older. Dirt and corrosion can be removed by cleaning the metal connections. This will ensure that the new bulb will make proper contact with the existing bulb when installed.
  • When installing the replacement bulb, make sure it is securely fastened in place.
  • At the pilot light, replace the bulb holder with a new one.
  • If you have to remove the bulb holder, be sure to replace it.
  • Start the vehicle and step on the brake pedal to determine if the bulb is working properly.

2. Blown-out Fuse

This is the easiest point to verify. We can find out where the fuse box is located and which fuse is responsible for the brake lights by consulting the car’s owner’s manual. For those who have lost the owner’s manual or are not sure what to do, you can always check the fuses one by one.

To inspect the fuse, first, remove it from its original position. A brief glance should be enough to determine if the resistor is damaged or not. What you are looking for is the small connection that joins the two small metal plates, which can be seen through the clear plastic. It is also possible to use a multimeter if you cannot see it well. To do this, follow these steps:

  • Set the continuity function of the multimeter (represented by a speaker symbol and/or an arrow with a vertical line on the tip).
  • Position the test leads so that they are in contact with the fuse tabs.
  • A beep from the multimeter indicates that current is present; if there is no beep, it indicates that the fuse has blown.

If this is the case, it will be imperative to modify it to meet one of the requirements specified by the manufacturer (a fuse costs pennies).

In other words, it must have the same number of amperes as the one indicated on the top of the fuse. If we use a fuse with a lower amperage, it will blow the next time the brake lights are activated.

Take precautions! It is possible that the blown fuse is not the source of the problem, but the result of a larger problem.

A blown fuse can be caused by, among other things, an electrical short circuit or a frayed wire. If the fuse blows regularly, the electrical system should be thoroughly inspected.

3. Bad Bulb Socket

Moist conditions have the potential to cause damage to the sockets. You should be able to detect some discoloration on the socket if the problem is caused by a buildup of moisture in the socket.

If the socket plug is damaged, you will almost certainly notice that the light does not work. It is essential to be on the lookout for these obvious problems so that they can be fixed as soon as possible.

4. Worn wiring

The electrical system is responsible for making sure that everything works as efficiently as possible. Before proceeding with the inspection, it is necessary to make sure that the vehicle’s wiring diagram is in good working condition.

Additionally, in addition to inspecting the vehicle for frayed or damaged wires, you should inspect the ground circuit, which can sometimes create a problem with the taillights.

5. Brake pedal sensor

Every time we press the brake pedal, the brake lights come on. This occurs as a result of the presence of a sensor with a switch that, when pressed, turns the lights off. Once the brake pedal is depressed, the pressure is removed and the brake lighting system circuit is closed, allowing power to reach the lights.

Having a problem with the brake pedal sensor or switch is not unusual. The switch in question can be accessed by bending down and looking at the bottom bracket, which has a push-button that can be pressed in and out.

The first thing to look for is whether it has come loose or if there is something wrong with its installation. When the brake pedal is removed, the pushbutton must press firmly enough for it to be effective. If it does not, adjustments must be made to ensure proper contact.

Final Thoughts – Tail Lights Not Working

There may be other reasons why the taillight does not work and your brake lights do. It is possible that the socket holding the bulb has failed due to moisture ingress, which can also cause rust.

Most modern cars have ambient light sensors. If the sensor is dirty or damaged it cannot tell whether it is day or night outside. In general, you need your vehicle’s lights to work properly, as they can help improve road safety. You can be hit from behind by another vehicle if you drive a car without a taillight.

Therefore, you should determine the reason why a taillight is failing. You should also know how to identify a blown bulb and replace it when it occurs.

Liam

Hi, I'm the initiator and writer of this blog. Cars were and will be my first love, and my favorite hobby, that's why I decided to start this blog and write about my discoveries and techniques to improve my cars or repair them.