What Are Sealed Beam Headlights? (All You Need to Know)

If you don’t know much about cars from the 20th century, or the headlights that were used, you probably don’t know much about sealed beam headlights. Well, a law was created in the US in 1939 that all vehicles must use them for certain reasons.

One reason was for safety, efficiency, and consistency. Before ‘39, vehicles were using all sorts of options that just weren’t working. So, you may now wonder: what exactly are sealed beam headlights? If you’d like to find out, keep reading!

What Are Sealed Beam Headlights?

Sealed beam headlights are a complete one-piece assembly with a bulb sealed inside a glass or plastic lens. If a light bulb goes out, the whole assembly has to be changed. Although the law to use them was changed in 1984, they are still used, even on some brand new vehicles, and can be purchased from aftermarket dealers in [currentyear].

For the most part, sealed beam headlights are not installed on most newer cars, except for some that have low options. And although they are considered older tech, you can still purchase them today. To find out more, keep reading!

How Do I Know If I Have Sealed Beam Headlights?

Finding out if you have a sealed beam headlight vs the composite headlight, is as simple as recognizing if you can get to the light bulb inside the lens.

You can usually do this by opening up your hood and looking behind the headlight bezel/shell.

If you can decide if there is a way you can simply twist the headlight out of position, like it was meant to be pulled out, then you have a composite headlight.

Read More:  Are LED Headlights Legal in California? (Types + More)

If you open your hood and find that there is no access to the light bulb, not in the front of the headlight assembly or behind it, you have a sealed beam headlight.

Hint: To accomplish this task, you should not have to use tools or brute force, and if you do, then stop.

You have sealed beam headlights, and nothing you can do will make that headlight work again.

What Are the Advantages of Sealed Beam Headlights?

What Are the Advantages of Sealed Beam Headlights?

Although sealed beam headlights are older technology, they do have some advantages over new technology.

One of those advantages is that new composite headlights have a lot of problems with foggy lenses.

You don’t get this much with sealed beam headlights for two reasons. Since they are sealed, much less moisture tends to get inside, which causes oxidation/fogginess.

Also, when a bulb goes out, the whole unit gets replaced.

This gives you a new lens every time, so unlike composite headlights, you don’t have to scrub or clean the lens clear of the oxidation.

There is also another advantage, and that is price. Usually, older technology for anything tends to cost a little less, and sealed beam headlights are no different.

However, the biggest disadvantage you will notice is that new composite headlights tend to offer you more light bulb options that illuminate light much further and brighter than a sealed beam headlight can offer.

Are Sealed Beam Headlights Better?

If you are looking at the new technology that is available for your vehicle, then no, sealed beam headlights are not better.

However, if you look back to 1939 and what they replaced, then yes.

Read More:  Why Do Deer Freeze in Headlights? (Not What You Think)

The law to implicate the standard headlight system made a huge difference in the following areas:

  • Availability of headlights
  • Replacing headlights
  • Having headlights that were more efficient
  • Headlights that did not blind other drivers, while still offering more visibility

However, the biggest disadvantage is that new composite headlights tend to offer you more light bulb options that illuminate light much further and brighter than a halogen sealed beam headlight can offer.

How Long Do Sealed Beam Headlights Last?

How Long Do Sealed Beam Headlights Last? 

You would probably hope that, since you can’t change just the light bulb, your sealed beam headlights would last longer than they do.

Unfortunately, though, you will only get about 500-1000 hours out of your sealed beam headlights.

Can Sealed Beam Headlights Be Aligned?

All headlights can be aligned, but this type of task should not be taken on by a non-professional.

This type of project needs special tools and a know-how, and for good reason.

When headlights are adjusted by an amateur, someone may not only be adjusting them to hinder their own visibility at night, but also to impair other drivers or pedestrians’ vision.

How Do You Replace a Sealed Headlight Beam?

It’s pretty simple to replace a sealed headlight beam, since you will be replacing one full piece.

You can look for yourself and find whatever screws might be holding the headlight bezel/shell in place.

There could be some small ones in the front of the headlight, but there will be a retainer with a couple of screws in the back.

Once you are sure all screws or bolts that hold the light in place are taken out, use one hand, and slowly back the lighting fixture out.

Read More:  How Much Does it Cost to Replace Headlights? (All You Need To Know)

When you get it out far enough that you can see what it’s connected to, use your other hand to separate the connection from the headlight fixture.

Next, clean off any corrosion that was left behind on the connection.

Then, the new sealed headlight beam should go in as easily as the old one came out.

Since this is a commonly replaced part, to get an idea and maybe even a visual, your owner’s manual should give you some more detailed information.

Are All Sealed Beam Headlights the Same?

Are All Sealed Beam Headlights the Same?

Up until about the mid-1950s, all headlights were the same size, used the same lenses, and used the same three-prong electrical connectors.

As car companies wanted to give their consumers more options, headlights changed sizes, configures, and electrical connections.

However, to this day, the same general idea and workings stay the same for sealed beam headlights.

If you are looking to learn more, you can also see our posts on what are projector headlights, what are adaptive headlights, and what are OEM headlights.


Sealed headlight beams are older headlight technology that came into play when a law was implicated in 1939, that all car builders must implicate them on their new vehicles.

This law was an attempt to ratify all of the inefficient headlights that were being used at the time. The law stayed in effect until 1984, but the efficiency of the sealed beam headlight never died, and is still being used to this day.

Leave a Comment