Have you noticed your headlights are dim or flickering on a dark road?
It might be time to learn how to change headlight bulbs.
But before you roll up your sleeves to change a headlamp, it’s worth double-checking whether your headlight woes are due to a burnt-out bulb or if there’s a sneakier culprit at play.
This guide will walk you through everything you need to keep your headlights shining bright.
This Article Contains:
- What Causes Headlights to Fail?
- How to Change a Headlight Safely and Easily
- What if the Replacement Bulb Doesn’t Work?
- 4 FAQs about Car Headlights
What Causes Headlights to Fail?
Understanding the common reasons for headlight failure, including a blown headlight, can help you address the issue before it becomes a safety hazard. Here are some of the most common causes of headlight failure:
- Old age: Like any other component, your headlights wear out with time. Engine vibrations or normal wear and tear can eventually wear out the filament, leading to a blown headlight.
- Temperature fluctuations: The filament inside your headlight bulb expands and contracts as the temperature changes. Extreme cold, followed by warm temperatures, can shorten your bulb’s life.
- Oxidation: Oxidation of the headlight housing can cause the light to become dimmer or yellower, especially with newer halogen headlights.
- Damaged light housing: A halogen bulb is particularly susceptible to moisture. Even small cracks in the headlight housing can let in moisture and humidity, compromising the light bulb.
Now that we’ve covered why headlights can fail, let’s explore how you can change a headlight yourself.
How to Change a Headlight Safely and Easily
Before you get a new pair of headlights, you must determine whether you have a faulty headlight or a blown fuse. If your vehicle uses sealed beam headlights, you may need to replace the entire headlight assembly.
Remember, traffic safety can be compromised if your headlights aren’t functioning correctly, so it’s important to address the issue quickly.
Here’s how you can test it:
Keep your car parked and turn on the headlight. Now, walk over to the front of your vehicle and check if only one or both lights are out.
If it’s just one, you need a headlight replacement, but you’re likely dealing with a blown fuse if it’s both. You should conduct a quick fuse test to ensure the headlight problem is genuine and not caused by a faulty fuse.
If the fuse is fine, follow these steps to change the headlight:
Note: If you’re not comfortable dealing with car parts, get help from a professional mechanic.
Step 1: Safety First
Park your vehicle on a flat, well-lit surface and engage the parking brakes. Then, disconnect the negative terminal on the battery.
Step 2: Access the Headlight
This part may be more challenging in some vehicles than others. In some cars, you may need to remove the air filter, battery, or other components to access the headlight holder.
Once those are out of the way, find the headlight backing behind the bulb housing.
Step 3: Disconnect the Headlight Wires
Unscrew and remove the dust cover from the back of the headlight. After that, find the metal clip or screws securing the power connector and carefully release them.
Disconnect the headlight wires from the light bulb holder, being careful not to apply too much force to avoid damaging the connector.
Step 4: Remove the Old Headlight Bulb
Now, it’s time to remove the old bulb. Some bulbs screw in, but for most, you’ll need to disengage the locking tab. Be gentle while removing the old bulb to avoid damaging any locking tab in the bulb housing.
Note: For an older vehicle with separate bulbs, you’ll need to identify the high-beam and the low-beam bulb. The low beam bulb is generally found on the outer side of the headlight, while the high beam is on the inside.
Step 5: Install the New Bulb
Insert the new bulb into the headlight holder and secure the locking tabs. Remember to wear gloves while doing this to avoid contaminating the headlight bulb replacement. Reattach the headlight assembly to the car’s body, and don’t forget to connect the other components you removed during the process.
Tip: You should always get replacement headlight bulbs in pairs. Usually, when one bulb dies out, the other isn’t far behind.
Repeat steps 2 and 5 to install the new headlight bulb on the other side.
Step 6: Do a Quick Test
After you install the headlight bulb replacement, turn on the ignition and test the new headlight. Cycle between the high beam and low beam to ensure the new headlight bulb works correctly.
Tip: It’s a good idea to check your brake lights while you’re working on your car lights since brake lights often have shorter lifespans.
If it’s all good, your new headlight bulbs are ready for the road.
But what if you’ve installed the replacement and it still doesn’t work?
Let’s find out.
What if the Replacement Bulb Doesn’t Work?
If your replacement bulb doesn’t work, you might be dealing with a deeper headlight problem, which means testing the fuses and wiring harness. It’s easy enough to replace a blown fuse, but things become complicated when dealing with damaged wiring. You’ll need to check for broken wires, poor connections, or issues with the headlight switch or relay.
However, the process doesn’t end there. Here are two other key considerations:
- Compatibility: Ensure the new headlight bulb is compatible with the socket. For example, Halogen bulbs run hot, and some aftermarket options can burn even hotter.
- Potential issues: The additional wattage in Halogen bulbs can cause the plug or wiring harness to burn out or melt, damaging the connection. If that happens, you’ll need to replace the entire headlight assembly.
So, it’s best to leave this job to a skilled mechanic to ensure you maintain working headlights.
Next, let’s answer some frequently asked questions about car headlights to help you avoid any future issues.
4 FAQs about Car Headlights
Here are answers to three common queries about car headlamps:
1. How to Conduct a Fuse Test?
Here’s how you can do a fuse test:
- Locate the fuse box: Look at the owner’s manual to find the fuse box. It’s normally located in the dashboard on the driver’s side.
- Identify the fuse: Find the fuse you want to test by referring to the fuse diagram in the owner’s manual or inside the fuse box cover.
- Test the fuse: Set the multimeter to DC and connect the black terminal to the negative battery terminal. Activate the parking brake and turn the ignition on. Then, check both sides of the fuse with the positive terminal of the multimeter. If both sides show 12V, the fuse is good.
2. What Are the Signs of Failing Headlights?
These signs point to headlight failure:
- Dim or flickering headlights: If your working headlights seem dimmer than usual or flicker on and off, it could indicate worn bulbs, a loose connection, or a wiring issue.
- Only one headlight works: Regular use or faulty wiring can cause one headlight to burn out and stop functioning.
- Only the high beam works: If each high beam works fine, but the low beams don’t, or vice versa, it could be that one of the bulbs is burned out or you have a wiring problem.
- Frequent fuse failures: If you have consistent headlight issues and the fuse keeps blowing, there’s likely a problem with one of the bulbs. It’s best to have a technician diagnose the underlying problem.
3. What Are the Different Types of Headlight Bulbs Available?
You should always check your owner’s manual to find the type of bulb and housing compatible with your vehicle. Here are the common types:
- Halogen bulb: Halogen headlights contain halogen gas and a tungsten filament to produce a yellow-tinged light. A halogen bulb can last 450 to 1700 hours but cause glare if improperly aligned.
- LED (Light-Emitting Diode) bulb: An LED headlight produces light by passing an electric current through a microchip. An LED bulb produces cool, bright light that lasts for 10,000 hours.
- HID (High-Intensity Discharge) light: HID headlights produce light as bright as an LED headlight. The glass bulb gives off a cool white or blue light when heated. HID headlights last longer than halogen lights but not as long as LED bulbs.
4. How to Select the Right Bulb?
In addition to the recommended type, look at the following points:
- Lumens: Higher lumens mean brighter light, but overly bright bulbs can cause glare for other drivers.
- Color temperature: Measured in Kelvin (K), color temperature changes how the light looks. Lower Kelvin numbers give a warmer yellow light, while higher Kelvin numbers produce a cooler, bluish light.
- Beam pattern: A good beam pattern spreads the light evenly and reduces glare, which is especially important for an HID and LED bulb.
- Energy efficiency: Consider the bulb’s energy consumption. LEDs are the most energy-efficient, while halogens consume more power.
- Durability and lifespan: LED and HID bulbs generally last longer than halogen bulbs, which might save you money in the long run.
- Legal requirements: Some high-intensity bulbs may only be legal in some places. Make sure the bulb you choose follows local regulations.
Shine Bright on the Road with AutoNation Mobile Service
Replacing faulty headlights is crucial for optimal visibility and ensuring your safety in traffic. If your vehicle uses separate bulbs for high and low beams, it’s important to know how to replace each one correctly.
However, if you’re unfamiliar with auto parts and need a headlight replacement, call in the professionals — like AutoNation Mobile Service.
We’re a mobile auto repair and maintenance service available seven days a week. We provide convenient online booking and a 12-month, 12,000-mile warranty on all repairs.
Contact us, and we’ll have your headlights shining like new!