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BMW 540i Tail Light

How to Troubleshoot Your BMW 540i Tail Light

Your BMW 540i tail light is one of the main safety features of your car, and is used as a communication tool to other drivers especially when driving under low-visibility conditions. With this component, you are less likely to get crashed into by another car behind you. Because of its importance, some states require all cars to have properly working tail lights. Driving around without this component can earn you a ticket and a fine. Avoid these inconveniences by repairing or replacing your tail light immediately. If you don't know what's wrong with it, you can always troubleshoot it by looking for these three common problems.

Loose or broken bulb

The first and probably the most obvious cause of tail light failure is a loose or broken bulb. Because bulbs are considered wear-and-tear items, it is normal for them to become loose over time. To check for any loose or broken bulb, remove the tail light lens using a screw driver or a ratchet and socket. Then inspect the filament in the bulb to see if it's loose or broken. If it's broken, replace the bulb with a new one. If it's loose, remove the bulb and reinstall it, then check if it's correctly placed. If it's still not properly installed, then the bulb might be incompatible with the assembly and you will have to buy the correct one.

Bad connection

If there's nothing wrong with the bulb, then there's probably something wrong with the wires connecting the tail light to other components such as the brake pedal, the modules, and the battery. Inspect all the connection between the wires and the sockets; know which one connects to which part. If you find a bad connection, don't repair it by yourself unless you're an electrician. Instead, take your car to a professional and have it repaired.

Blown fuse

Because every electrical component is powered through a fuse, a blown fuse in your car can cause the object wired to it to fail. So if the entire tail light is busted instead of just one bulb, then chances are the failure is caused by an electrical problem that led the fuse to blow up. You can find the tail light's fuse in the power distribution center, also known as the fuse box. You can refer to your owner's manual to see where the tail light's fuse is exactly located in that box. You'll need a connect test light to check whether the fuse is working. If it's already faulty, then simply replace the fuse.

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  • Some Basic Tips on Cleaning Your BMW 540i Tail Light

    Just like the headlight, your BMW 540i tail light signals your presence to other drivers behind you-this is especially important when you're driving under low-visibility conditions. Because it's one of your car's main safety features, you always have to keep this component bright and clear. To maintain this, you have to regularly clean the tail light and restore it to mint condition if possible.

    General cleaning tips

    • Use a regular-cut polish for cleaning the tail light and follow the instructions indicated in the container. While this product is actually used to clean painted objects, a regular-cut polish is also an effective lens cleaner. It can easily remove the haze on the plastic tail light lens. You can also use Turtle Wax if preferred.
    • Before using any polish on the tail light lens, wash the component first to get rid of dust, dirt, and small insects that may be on the lights.

    Restoration tips

    • Before sanding the tail light, protect the surrounding area by placing several layers of masking tape around the component. Make sure that the layers of tape are thick enough to keep the sandpaper from cutting through and scratching the paint.
    • To ease the roughness of the sandpaper, soak it in the water and begin sanding the tail light. Maintain a left to right direction when moving the sandpaper-do not move it in circles or up and down.
    • Keep the sandpaper wet while sanding to prevent it from making deep scratches on the lens.
    • You may use two different sandpapers-a 1200- and a 1500-grit-to better clear out the tail light's lens.
    • After sanding, rinse the component with water and let it dry completely.
    • You can also use a regular-cut polish to achieve a new look for your tail lights. When polishing, work it on the lens in small circular motions. Don't stop until you find the component looking bright and clear and without any dull areas that were caused by the sanding process.
    • If you have a UV protectant that's made for plastic, apply it on the tail light with a clean microfiber towel to protect the component from future oxidation.