5 Reasons Why Your Toyota Headlight System Malfunction

Why Your Toyota Headlight System Malfunction

If you own a Toyota, you may have experienced a headlight system malfunction. Several things could cause this problem, but the usual culprit is an issue with the headlight relay. The headlight relay gives power to the headlight bulbs. If it doesn’t work, the headlights won’t turn on. In this article, we will discuss the top 5 reasons why your Toyota’s headlight system may have malfunctioned.

1. Burnt-out Headlights

The most common reason for a headlight system malfunction is burnt-out headlights. The headlight system will warn you if a headlight is about to burn out. Usually, a headlight should work for at least 1000 hours. Some headlights last much longer than that, but 1000 hours of illumination time is standard. When a headlight stops working, you have to put in a new one. Headlights are usually sold in pairs. If you buy a pair, it’s a good idea to change both of them.

2. Auto-leveling headlights are not working.

Auto-leveling headlights are smart headlights. They adjust to the car’s position, keeping the light on the road. These headlights move by themselves. Sometimes, they get out of place, and the sensors can’t figure out where they should be. To fix a problem with auto-leveling headlights, first look for a warning light for the system. If it’s blinking, take your Toyota to a certified mechanic for a diagnostic test. If your Toyota is still under warranty, use the manual to find the fuse connecting the computer to the headlights. If the fuse is blown, the computer can’t communicate with the headlights to run the auto-leveling program.

3. Water or Mud Found Its Way into the Headlight

Sometimes, sand, mud, or water can get into the gaps around the headlight cover, making the headlights dirty. If you notice particles inside the headlight cover, remove them and clean the headlights and the surrounding area. If it’s really dirty, you might have to take out the headlight and clean the socket. Make sure to clean all the sensors too. Sensors can malfunction if they get dirty or wet. Note: If you live in a rainy or humid area, make a habit of checking under your headlights regularly.

4. Bad Relay, Module, or Fuse

Headlights may stop working because of a faulty relay, module, or fuse. Issues with wiring connections can also be a problem when both headlights stop working. If your high beam or low beams don’t work, it could be because of a problem with the relay or high beam switch.

5. Corroded Battery Terminals

Corroded battery terminals can also cause the headlight system to malfunction. If the battery terminals are corroded, then the battery will not be able to provide enough power to the headlight system. In order to fix this problem, you will need to clean the battery terminals. You can do this by using a wire brush or a battery terminal cleaner. Be sure to wear gloves and eye protection when cleaning the battery terminals.


In conclusion, there are many reasons why your Toyota’s headlight system may have malfunctioned. The most common reasons are burnt-out headlights, auto-leveling headlights not working, water or mud finding its way into the headlight, a bad relay, module, or fuse, and corroded battery terminals. If you experience any of these problems, it is important to take your Toyota vehicle to a certified mechanic to have them run a diagnostic test. By doing so, you can ensure that your Toyota’s headlight system is working properly and that you are safe on the road.

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