Have No Tail Lights When Headlights Are On? Here’s Why

A vehicle’s tail lights are supposed to turn on when its headlights are activated, while the brake lights are supposed to illuminate when you step on the brake. However, there are situations where your vehicle’s brake lights work, but not its tail lights.

Tail lights function similarly to a vehicle’s headlights, allowing other drivers to see your vehicle in low-light situations. Without functioning tail lights, your vehicle will be at risk of being rear-ended by other vehicles. If your vehicle has faulty tail lights, then you’re also at risk of being pulled over because tail lights are mandated by law.

In some vehicles, brake lights and tail lights use the same light bulb. Although brake light and tail light problems are similar, the root causes could be different.

Here are possible causes of malfunctioning tail lights:

Blown Fuse

Vehicles are equipped with fuses that protect the tail light bulbs and brake light bulbs from voltage surges. If the fuse that corresponds to your tail lights bulbs has burned out because of a voltage surge, then the circuit will be broken and your tail light won’t activate. Your vehicle’s brake lights can still work even when its tail light fuse has been blown.

Bad Tail Light Bulb

If your vehicle’s tail lights and parking lights are not working, a faulty tail light bulb might be the culprit. The brake light and tail light often use a single dual filament bulb. This means that there are two filaments in one bulb. One filament illuminates when the driver presses on the brake pedal, while the other illuminates when the tail lights are activated. There are situations where a faulty dual filament bulb can still allow the brake light to illuminate when the filament that corresponds to the tail lights is broken.

You can determine whether your vehicle has this issue by closely observing the tail light bulb. If there’s a filament that isn’t illuminating, then you should replace your tail light bulb.

Faulty Tail Light Socket

A faulty tail light socket can prevent power from reaching your vehicle’s tail light bulbs. Water, dust, and air can enter the tail light assembly when it isn’t properly sealed with silicone.  These elements can allow rust and corrosion to form, which can affect the socket’s ability to conduct power to the tail light bulbs.

If the socket or connectors has signs of heat or melted plastic, which can be brown, blue, or white discoloration, then it likely has a problem. The headlight assembly could also have faulty pins, which can cause connection issues with the wiring harness.

Faulty Ambient Light Sensor

Some vehicles are equipped with ambient light sensors that detect outdoor lighting conditions, allowing headlights and tail lights to activate when it’s dim outside. When this sensor develops issues, the tail lights might not activate when needed.

Faulty Wiring

Your vehicle’s tail lights use wires to connect to the battery. If the tail lights and parking lights aren’t working, then there’s a chance that your vehicle has faulty wiring or a damaged electrical ground wire.

Overall, your tail lights can stop functioning because of several possible reasons, such as a faulty bulb, a blown fuse, or a rusted light socket. While you can attempt to fix your tail lights yourself, it’s best to leave it to experienced mechanics because the process will likely involve a thorough inspection, which might require some components to be disassembled. Fixing your vehicle’s tail lights without the right know-how is risky because you run the risk of creating new issues. Good thing there are helpful online resources that can help you replace your tail light yourself if you feel like you’re up to the job.

Get Replacement Tail Lights and Bulb Sockets Online

Tail lights are an important safety feature, as they allow your vehicle to be seen from behind. Without functioning tail light assemblies or tail light bulb sockets, you risk being rear-ended at night. You shouldn’t drive with malfunctioning tail lights because it’s a risk to you and your passenger’s safety. Luckily, finding the right components to restore your tail light assemblies and bulb sockets is easy and convenient here at CarParts.com. 

We have a wide range of replacement tail light assemblies and bulb sockets. Our components are built following the original part’s specifications, ensuring perfect fit and function. Aside from high-quality parts, we also take pride in our strategically located warehouses that allow us to ship our products fast.

So what are you waiting for? Shop for replacement tail lights and bulb sockets here at CarParts.com today!