Your Guide to Figuring Out the Right Type of External Car Light Bulb to Buy

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Your Guide to Figuring Out the Right Type of External Car Light Bulb to Buy

External car lights are essential for vehicle safety and driver comfort. They perform several different functions, such as illuminating the road, making the car visible to other drivers, and indicating turns or other driver actions. When it comes time to replace or upgrade a bulb,, it can be a daunting task to find the right one. Variables range from the type of light, the type of bulb, and the bulb fitting. 

Buyers first need to determine what type of light needs replacing: there are several external lights on a standard vehicle, and some have additional auxiliary lights. Next, the type of bulb needs to be determined, whether incandescent, halogen, LED, or xenon HID. Finding the right car bulb fitting is another vital step in this process: these are determined by the vehicle's make and model, and there are many online databases to help find the right fitting if the owner is unsure. Once the type has been determined, there remains the process of deciding on a product; in this case, buyers should have some familiarity with basic specification terminology, as well as the most well-known brands. Following these steps helps them pinpoint a reliable bulb that is right for their car.

What Type of Light?

A car has several different kinds of lights: headlights,, indicators,, rear lights,, and front sidelights are the most basic, and some models may feature fog lights or daytime running lights (DRL). The first step when replacing a bulb is determining exactly which bulb needs to be replaced. To test a car's lights, park the vehicle in an area free of traffic and out of the sun, turn it off, and apply the parking brake. Open the driver's-side door and turn on the headlamps. Test the main and dipped beams, and then check each indicator, both left and right. Finally, test parking lights and fog lights or DRLs if available. To test the rear lights, have an assistant apply the brakes, and check that all lamps are illuminated. Next, have them turn on the left and right indicators, and finally the park lights. Any lights that do not illuminate when switched on need replacing.

Different Types of External Car Light Bulbs

There are four major types of car light bulbs: incandescent, halogen, LED, and xenon HID. Choosing a type of bulb depends largely on a car's specifications. However, bulb types also vary in terms of power consumption, life, and brightness, so these should also be taken into consideration.

Incandescent Bulbs

Incandescent bulbs have for many years been the conventional car bulb, and are still standard for many automobile manufacturers. The incandescent bulb features a tungsten alloy filament. Tungsten is a rare, hard metal of unusually high density. When the car's external lights are switched on, an electric current is sent through the filament, heating it and producing a glow. Because tungsten has such a high melting point, it is able to withstand this heat. Gradually, however, the filament evaporates, leading to weak spots. When one of the weakened points breaks, the bulb requires replacement.

Filament structure is important in incandescent bulbs. While thicker filaments are more durable, thinner ones burn more brightly. Manufacturers can deal with this in a number of ways, including coiled or geometric filaments that increase capacity, allowing for a longer filament in a smaller space.

One advantage of incandescent bulbs is that the heat they generate defrosts the lens during cold conditions, allowing for maximum visibility even during ice and snow.

Halogen Bulbs

A halogen bulb is a specific type of incandescent bulb in which the filament is encased in halogen gas. As the tungsten evaporates and moves away from the filament, this gas carries it back to the filament. This differs from conventional bulbs, in which the evaporated tungsten collects on the bulb wall. The result is a longer-lasting filament that produces a bright, white light. However, because the halogen gas cannot return the tungsten to the exact place on the filament from which it came, weak spots slowly develop, and the filament gradually breaks. The average life of a halogen bulb is 1000 hours.

In addition to being durable and bright, the halogen bulb is inexpensive to replace, and comes in a variety of sizes and shapes to match different bulb fittings (discussed below). There are, however, a couple of disadvantages. First, they generate a high amount of heat, which may be regarded as a waste of energy. Also, the special type of glass used for the bulb itself requires careful handling: for example, salt from the skin could reduce its heat resistance, so it must not be touched with bare hands.

LED Lights

Light-emitting diode (LED) lights have emerged as a newer type of bulb with several distinct advantages over incandescent bulbs. LED lights feature a group of small LED bulbs that can be set in any configuration. LED bulbs are attached to a semiconductor; electron movement along the semiconductor illuminates the bulbs. They emit significantly less heat than incandescent bulbs, making them more energy efficient, and they have a long life.

LEDs have a few disadvantages, however. One major consideration is production cost, which is quite high. Next, although they do not emit much heat, they do produce heat at the base of the emitter, which could potentially damage adjacent parts. For this reason, manufacturers have been slow to use LEDs in headlamps. They are used, however, in indicators, brake lamps, and DRLs. Finally, they are not as powerful as their halogen and xenon counterparts. But as the auto manufacturing evolves, this problem is likely to find a resolution.

Xenon High-Intensity Discharge (HID) Bulbs

Xenon bulbs,, also known as high-intensity discharge (HID) bulbs, operate in yet another way. They contain two electrodes, rather than a filament, and are filled with xenon gas. Electrons jump between the two electrodes, and the ionised xenon gas amplifies the light this process produces. The xenon in the bulbs also gives them a bluish light. The light from xenon bulbs is over twice as strong as that from halogen, and their lifetime has been estimated at 2000 hours. They operate at a higher voltage and require a ballast, which is a type of transformer. However, they draw about half the energy of conventional bulbs, and are therefore regarded as more energy-efficient.

Potential Issues with Xenon HID Bulbs

There are several considerations with xenon bulbs, however. The primary concern is that the brightness and focus of their beam requires custom HID self-levelling in the lamp itself. HID bulbs used in conventional headlamps could blind oncoming drivers and pose a significant safety hazard. For that reason, it is illegal in the UK to use an aftermarket HID bulb to upgrade a halogen lamp. For those that wish to upgrade to HID bulbs, it is required that they install HID-approved headlamps first.

There are two other disadvantages to xenon HID bulbs. First, they are expensive to buy, replace, and install. Second, some xenon bulbs may contain potentially toxic substances, including metal mercury. Buyers should research the bulbs they are interested in to verify how safe they are.

Car Bulb Fittings

Bulb fittings refer to the type of bulb required by a vehicle. For headlights, incandescent bulbs can be categorised as one of two types: in the first, there is one bulb for both main and dipped beams; in the second, there are separate bulbs for the dipped and main beams. The first type has two filaments, one that is always illuminated, and a second that switches on with the main beams.

There are a few ways to determine which type of bulb is required. The Internet has many sites where vehicle owners can enter the make and model of their car to find out which bulb fittings they need for the particular light to be replaced. Alternatively, they can call a vehicle repair service for consultation.

The following chart outlines the most common bulb fittings.

Bulb Type


H4 (472)

The most common bulb fitting; two-filament bulb with three-pin connection

H1 (448)

In two-bulb setups, the most common bulb used for main beam; single-pin connection

H7 (499)

In two-bulb setups, the most common bulb used for dipped beam; two-pin connection


Xenon gas bulb; intended for reflector housing


Xenon gas bulb; intended for projector housing

The majority of vehicles require one of the above-listed bulbs; however, there are other types, including H11,, HB3,, and HB4.. It is essential to find the right type of bulb fitting for the car's make and model, as incorrect fittings do not function.

Understanding Bulb Specifications

There are a few important specifications which buyers should note when comparing different bulbs. These include power consumption, light output, and bulb life. 

Power Consumption

The amount of power a bulb consumes is indicated either in amps, watts, or volts. Power consumption is not an indication of brightness.

Light Output

Light output is most commonly denoted in lumens. This specification is important in terms of comparing brightness of different bulbs.

Bulb Life

The life of a light bulb is indicated in hours, which approximates how long the bulb should last. This specification is also particularly important, and should be taken into consideration alongside replacement costs.

Choosing Leading Manufacturers

The majority of car bulbs used by manufacturers are either Philips or OSRAM.. While buyers may pay slightly more when choosing these brands, they can rest assured that they are purchasing the industry standard, and are therefore more likely to get a quality, high-performance product.    

How to Buy External Bulbs for Your Car

Car bulbs can be purchased at a number of places. In person, consumers can shop for bulbs at automotive supply centres. Online, they have a range of choices: they can buy from Internet merchants specialising in auto supplies, directly from the manufacturer, or through an online auction website like eBay.

Determining What is Road-Legal

It is highly important that consumers determine what kinds of bulbs are road-legal for their vehicle. Some types, such as xenon HID bulbs, may be advertised as "road-legal", when in fact they are legal only for specifically-fitted cars. When considering changing the type of light bulb that their car has heretofore been using, consumers are advised to check what the latest regulations are with the Department for Transport.

How to Buy External Car Light Bulbs on eBay

eBay has an extensive selection of external car light bulbs. With new listings every day and competitive pricing, eBay gives buyers a range of choices and lets them compare products with ease. To start, go to eBay's home page and enter keywords, such as "H4 bulbs&" or "Nissan indicator bulbs&", into the search bar. The more specific the search terms, the narrower the results are. You can then select things like bulb manufacturer, price range, and seller location, to further refine your choices.

Reading Product and Seller Information

When you've found a product of interest, click on it to see the full listing. Always look carefully at the item description, noting specifications, quantity, condition (new or used), and any other important details. Check whether there are additional postage fees, and what the seller's return policy is.

It is also a good idea to glance at the seller's feedback score and browse comments left by previous customers. This helps you assess their reliability and knowledge level, so you can buy with confidence.


Finding the right car bulbs for a car can be a daunting process. Whether replacing burnt out bulbs or upgrading to a better bulbs, it is important for buyers to have some understanding about the different kinds of bulbs available, how to find the right bulb fitting, and what the most important product specifications are.

The four types of car bulbs are incandescent, halogen, LED, and xenon HID. Incandescent were the standard for many years, but halogen, a subtype of incandescent bulbs, have become increasingly popular because of their longer life and low cost. LED bulbs employ LED technology for a durable and energy-efficient light, while xenon HID bulbs are yet another option that has become more prevalent. These bulbs are touted as having a very long life and bright, sharp beam. Choosing a type of bulb also involves finding what bulb is required for the vehicle's make and model, as well as the particular light on the car, such as headlights, brake lights, indicators, or other light.

If still having problems finding the right bulb for their car, consumers can consult one of many online databases or a car maintenance specialist. Following these steps helps them get the correct quality, dependable bulb for their vehicle.

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