How to Fix Car Tail Lights

We are all familiar with the significance of lights in a car but there are many factors that affect the lights and their performance which can lead to failure and sacrifice safety. This can particularly occur when bulbs inconspicuously fail and require immediate replacement or you will likely get pulled over and even fined. The taillights are extremely significant as they allow the drivers following you to understand your movements and act accordingly. If the taillights are broken, there is a higher probability of accidents happening. So if your tail lights are failing or have already died, then you should have them replaced immediately. 

Let us first understand the types of bulbs used in automobiles which can help us shed some light on how long bulbs last and how often you must think about having your vehicle bulbs replaced before their critical endpoint. 

Incandescent Bulbs 

These are the oldest technology in electrical bulbs and are the first type of lights used on a large scale. They featured a metal filament usually made of tungsten which when supplied with electricity illuminated and provided a small source of light, best described as a spotlight, onto the road. These lights were prone to failure due to the tungsten filament burning out after a short service span. To counter this issue the chamber enclosing the filament was sealed and the filament was kept in a vacuum. This gave rise to the commonly known vacuum incandescent light bulb. This technology further evolved and led to the development of halogen bulbs which were filled with halogen gasses. 

Vacuum incandescent bulbs were not very efficient and gave very little illumination to the road. They provided a very short service lifespan. Today’s car does not feature these types of bulbs so you may rest assured unless you have a beetle from the 1950s with factory lights. 

Halogen Bulbs 

Although halogen bulbs were invented in the early 1900s they only became part of the automobile in the 1960s. Like their predecessor, halogen bulbs also have a tungsten filament (sometimes more than one filament is used for high and low beams) but give away many of the drawbacks that the former carried. Halogen bulbs work based on a process called the halogen cycle which allows the tungsten filament to last much longer and provide a healthier service life and have better illumination since they can be heated to higher temperatures without failing. 

Halogen bulbs are still used in modern vehicles primarily due to their cost-effectiveness. Newer designs and models of halogen bulbs are more efficient than the first incarnations but are far less superior to the newest technologies. They are sufficient for most daily users and are cheap to replace when they go out, which they are certain to. High-quality Halogen bulbs have a service life of about 1000 hours. 

Xenon / HID Bulbs

Technically known as Light Arc Gas Discharge bulbs, Xenon lights work based on the physical principle of electrical discharge. These lamps do not have a filament and instead are illuminated by an arc that is created as electricity passes from one electrode to the other in the presence of xenon gas within a sealed chamber, hence the name xenon. These are also referred to as HIDs or High-Intensity Discharge lights. The electricity supplied is controlled via electronics that help start and maintain the bulb’s output and thus comes with a ballast unit that regulates the voltage for the proper functioning of the light. 

Xenon bulbs provide many advantages over halogen bulbs. They illuminate brighter and farther than filament-type lights while consuming less electricity, making them more efficient. Xenon also lasts longer than halogen bulbs making them even more durable. HIDs have a higher colour temperature which means it resembles sunlight more closely which is favorable for the driver. Xenon bulbs are widely used in modern cars but due to their expensive cost of manufacturing, are only limited to top-end models. These bulbs last about 2500 hours before needing replacement. 

LEDs

Light-Emitting Diodes or LEDs are the most superior light source available in automobile applications. At its heart, an LED is a semiconductor that emits light in a certain configuration when electricity passes through it. LEDs are able to emit bright white light (similar to sunlight) and use very small amounts of electricity in the process which makes them extremely efficient. They are much smaller in size and produce very high illuminance or a strong light source and require no maintenance for proper operation. Many high-end models now carry high and low beam headlights with LED applications. LEDs also last the longest of the bunch at about 25,000+ hours (actual rating can be even higher) of service lifespan. The only drawback to LEDs is their high cost which makes them very expensive for application in low-priced models. They are also costly to replace when they do fail.

Many vehicles have LEDs as DRLs or Daytime Running Lights along with either filament type or xenon headlamps. DRLs are a great feature found in many new vehicles as these lights are always on with the ignition and also provide a distinctive look to every car. LEDs are also used as interior lights, brake lights, and indicator lights.

Before you set off to replace the bulbs, you might want to check a few things as the reason the bulb went out could be due to other reasons like a blown fuse, torn wires, bad circuits, or even corrosion in the sockets. Figuring out the reason for the bulb failure will prevent the new bulb from failing prematurely. 

A. The first step is to check how many lights are not working. 

• If just one light is broken then the problem could simply be the bulb. However, depending on the vehicle model, there could be separate fuses for the right and left tail lights. So start by checking the fuse box for blown fuses. You can check a bad fuse using a multimeter on the continuity setting. If the fuse is fine then you can jump to replacing the bulb. If the fuse is bad, replace it and then check the lights.
• If all the lights are not working, then the issue could be due to a bad brake light switch. This switch is activated when the brake pedal is pushed. If the switch is broken, the lights will not be actuated. 

B. The next thing you can check is the tail light socket. Check for corroded ends in the terminals or torn wires. If the wires have detached from the plug then reattach them in their designated place. 

C. In most modern cars, you can use an OBD or scan tool to determine any faults with the tail light system and diagnose the problem more thoroughly and easily. So if you have a scan tool you can use that to find issues in the system. This will give you error codes or more information regarding the problem you are having. 

The bulb replacement can be a bit different depending on the vehicle’s make and model. There are two common methods of replacing the bulbs. Method 1 applies to most sedans where the tail light can be accessed through the trunk. Method 2 usually applies to trucks and vans where you need to remove the tail light housing to access the bulbs. 

Method 1

Step 1: With the ignition off, open the trunk and locate and undo the clips that hold the cargo floor carpet in place. Pull back the carpet from the end to access the tail lights, 

Step 2: Now you can see the wires connecting to the tail lights. There may be a small panel covering the sockets. Locate the socket with the broken bulb and gently remove it. You may need to twist it to the left to remove it. 

Step 3: Next, gently remove the bulb from the socket and replace it with the new bulb. 

Step 4: Reinsert the panel and make sure the wiring harness is properly connected. Put back the carpet and reinsert the clips. 

Step 5: Check to make sure the light is now functioning. 

Method 2

Step 1: With the ignition off, open the tailgate or trunk lid. The tail light housing is attached with some bolts that need to be removed to access the bulbs. These bolts may be hidden behind small plastic covers. 

Step 2: Remove the cover and undo the bolts to detach the tail light housing, 

Step 3: Now you can see the wires connecting to the tail lights. There may be a small panel covering the sockets. Locate the socket with the broken bulb and gently remove it. You may need to twist it to the left to remove it. 

Step 4: Next, gently remove the bulb from the socket and replace it with the new bulb. 

Step 5: Reinsert the socket and the tail light housing in its place. Redo the bolts and put back the plastic covers.