Your Bulb Questions Answered


If your bulbs have seen better, brighter days, you want to find a worthy replacement or upgrade as soon as possible. But picking the right ones for your application isn’t as simple as choosing a steering wheel cover or a bumper sticker. It takes a certain degree of knowledge about what you currently have and how it all works together. Here, we break down some of the most common questions folks have about bulbs, to make your buying experience a lot easier — and worthwhile.

Q: What’s the difference between halogen, LED and Xenon bulbs?

A: Currently the most popular type of headlight, halogen bulbs are packed with filaments made up of tungsten and halogen gas. When the electricity reaches the filament, the tungsten heats up, and then glows to let you know you have a charge. Don’t worry, though — the heat won’t cause damage to your auto. It’s an entry-level option that’s simple to replace when the time comes — and less expensive, to boot.

Stylish LEDs use negative electrons to produce photons, which generate a thousand times per second to create a strong, continuously burning light. The fact that there are no parts to wear them down over time means that they, too, boast a longer lifespan. This is partly due to their lower wattage. LEDs need to be cooled from the back of the bulb, and the headlight unit itself requires a different design.

(For a more in-depth comparison of halogen and LED lights, give this article a look.)

Xenon HID (High-Intensity Discharge) bulbs are quickly becoming the standard in new vehicles, largely because they produce a whiter, brighter light than their halogen counterparts. They tend to last longer and use electrodes to charge the xenon gas in the bulb.

Q: What if I have halogen lights but want LED or Xenon?

A: The short answer is that you’ll need a conversion kit. These are equipped with a specially-designed ballast to fit into your halogen bulb headlamp unit. The actual conversion takes minutes, and plug-n-play installation means they’re ready to go immediately.

Once installed, you’ll enjoy a sleeker, readier look and superior candlepower for the long haul. Generally speaking, conversion bulbs are rated for superior water-, dust- and shock-resistance, but each kit comes with its own unique benefits. The ProZ Universal LED Headlight Conversion Kit, for example, boasts instant ignition technology, while the Oracle Premium LED Headlight Bulb Conversion Kit features a concave reflector for a more fluid light pattern than the competition and reduced glare.

LED conversion kits are completely street-legal when properly installed, but the headlights must be aimed correctly to ensure you don’t blind oncoming traffic.

Q: How long does it take LEDs to light up?

A: While it turns off instantly, an LED can take up to a second to light up. Why? Because the electronics won’t start until they receive a sufficient charge. The capacitors also have to charge before the LEDs can finally be turned on. This is to avoid a massive inrush of current when it’s turned on.

The reason why it turns off so quickly is because while the LEDs are lit, it uses power but only stores enough to ignite between peaks of the incoming power. In a 60Hz circuit, for example, the peaks come at 120 times a second. To the human eye, that’s instantaneous. The capacitors within only carry enough energy to last through about 5 times that, which means that at about 45ms, the capacitors are too empty to produce sufficient voltage — and out go the LEDs.

Q: How easy is it to change a bulb?

A: No need to call your mechanic, as this task isn’t that difficult — but it will require a little effort and elbow grease. Before you begin, you need to have a few things in hand. First, there’s your trusty owner’s manual. Next, some rubbing alcohol or alcohol wipes — should you happen to touch the surface of the bulb, you need to wipe it clean to prevent damage.

Newer vehicles don’t use screws to hold any of the parts in place, but if yours is an older vehicle, you will need a screwdriver. Lastly, safety glasses are a good idea to keep your eyes safe. Now that you’re ready, here are the steps to change the bulbs:

  1. Pop your hood and prop it up.
  2. Remove the power connector from the back of the headlight. You might have to turn it a little bit to loosen the connector.
  3. Next, remove the dust cover from the back of headlight.
  4. Some vehicles feature a clip that holds the bulb in place. Press down on this clip to release the light bulb.
  5. Take a firm hold of the bulb housing and gently pull it out. It may take some wiggling beforehand, but be careful not to pull by the glass. You don’t want it to break.
  6. Tenderly wipe a pre-moistened alcohol wipe across the surface of your bulb to free it of dust and fingerprints. Rubbing alcohol on a clean cloth will suffice.
  7. Align the bulb housing with the open socket and make the insertion carefully.
  8. Slide the bulb back into place. If necessary, you may need to twist until it locks to ensure it’s absolutely secure.
  9. If you have one, replace the clip, then the dust cover and power connector.

Before closing the hood, turn your headlights on — if they do, you know that the bulb and connection are working as they should. Job well done!

Q: What bulb size do I have?

A: You shouldn’t eyeball anything if you want a precise measurement, and light bulb size is no different. No need to worry, though — we’ve eliminated any need for guesswork for you. Click here to use the Year, Make and Model (YMM) vehicle feature on our site, located in the upper right-hand corner. There you can specify what you drive and the bulbs that return in your search are the ones that match the size of your current bulbs. It’s as simple as that.


Hopefully, after reading through this list, you’ll feel better equipped than before you began. We think you’ll agree that the extra time you took will pay off in making the buying experience quicker, your final decision wiser and the road still-to-be-traveled that much safer. Happy (well-lit) trails.