How to Fix a Faulty Tail Light

tail light

How to Fix a Faulty Tail Light

A car’s tail light is designed to announce your presence to other drivers, particularly in low light conditions. They can malfunction for a number of reasons, such as cracked lenses, broken wiring or faulty bulb filaments.

If your tail lights are out, but the brake lights work, it could be a sign of a bad fuse. Check the fuse with a multimeter or by consulting your owner’s manual.


The tail lights, also known as brake lights and reverse lights are the red light at the rear part of a vehicle. These are a very important safety feature on vehicles. They help drivers to alert other road users about their position. Moreover, they are legally required on all cars and pickup trucks.

They may also be used as a turn signal on some cars tail light and other vehicles. Turn signals, also known as blinkers, are flashing lights mounted on the left and right sides of the car to indicate that the driver intends to change lanes or turn.

The most common type of tail light is the halogen bulb. This is a simple and efficient way to illuminate a tail light. However, the downside of halogen lights is that they produce a lot of heat and consume more energy. As a result, they are not considered to be the most eco-friendly choice for your car’s tail light.


Tail lights are a crucial safety component of vehicles. They announce the presence of your vehicle to other drivers during low-light conditions and can alert them that you’re slowing down. Unfortunately, they can malfunction due to a variety of reasons. These include cracked lenses, faulty bulb filaments and broken wiring. Fortunately, most of these issues can be easily fixed.

The three wires in a tail light circuit are ground, power and brake. The ground wire is typically black and is connected to a metal surface on your car or trailer. The power wire is red, and the brake light wire is blue. Some tail lights use a relay, which adds a fourth wire to the pigtail and acts as a “running light” when the switch is off.

When splicing the pigtail, start with the ground wire. Then, connect the red wire to the battery positive terminal and the blue wire to the brake light switch. The ribbing on the smooth side of the wire is usually your negative strand. The striped wire, on the other hand, will have a different texture, and can be identified by running your fingers along its length.


All vehicles require working tail and brake lights. These lights are used to warn other drivers of your presence on the road and to illuminate your rear end during low-light conditions. Some cars and trucks use one bulb for both lights (a dual filament setup) while others have separate bulbs for the tail light and brake light.

LED bulbs are a popular choice for tail lights due to their longer lifespan and brighter illumination. Traditional halogen bulbs need time to heat up and glow at their full brightness while an LED light immediately starts shining once current is passed through it.

Installing a new bulb is easy enough but make sure you’re buying the correct one for your vehicle. Depending on the manufacturer and your vehicle’s wiring setup, you may need to install a polarity decoder or CANBus compatible bulbs. Remember, tampering with your wiring could potentially void your car or truck warranty so it’s always best to consult your owner’s manual and/or the parts department of your auto store before attempting any DIY work.


The light bulbs in your tail lights are encased within what are called lenses. They both protect the bulb from moisture and ensure that the emitted light is in the correct color for its function. If you damage your rear lights by backing into a tree or power pole, or if the lens becomes discoloured you will need to replace it.

While the tail light lenses are a vital safety feature, they can be easily cracked by impact or heat and they are susceptible to the aging effects of UV and temperature changes. It’s also not uncommon for moisture to get into the lens which can short out your bulbs.

To make a new clear or colored lens, a rectangular form is created with enough room on the closest edges to accommodate the shape of the lens. Then strips of window pane glass are taped together and placed over the form. A small bead of silicon holds the glass to the base and seals any molding urethane rubber that may leak out of the form.


Your car’s tail lights are crucial to your safety on the road at tail light night and in low-visibility conditions. They also help other drivers see the rear of your vehicle and accurately judge its size and shape. So, if your tail light bulbs burn out it’s important to replace them right away.

Changing tail light bulbs is actually quite easy on most cars if you follow some simple guidelines. You need a basic set of tools and it should take only a few minutes to complete. Check out Haynes for more detailed step-by-step information.

To gain access to the bulb assembly remove the cover over the taillight socket (usually from the trunk compartment). Then, carefully jiggle and pull the assembly out, being careful not to break it.

When replacing the bulb(s) it’s a good idea to pour a little dielectric grease on the metal contacts to prevent water corrosion. It’s also a good idea to make sure you have the correct car bulb. If you don’t, it could cause a malfunction later on in your vehicle. Be careful to look at the old bulb and pay attention to the number of filaments (dual or single) and the base fitting.

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