Everything About Blue Dot Tail Light

Some of our younger readers, myself included, have most probably never heard of blue dot tail lights. Those same readers may also find it surprising that car modification trends were very much present well before the sixties, and blue dot tail lights were once one of those trends.

A blue dot tail light refers to tail lights with a small aftermarket blue lens installed right in the middle that, in combination with the standard red tail light, creates a purple hue. The tail lights may also come with the blue dot pre-installed, but such tail lights are aftermarket as well since blue dot tail lights were never offered as a factory option.

blue dot tail lights history

Blue Dot Tail Lights Explained

The blue dot tail lights history is an interesting one as it was a popular modification back in the 30s, 40s, and up until the late 50s. However, by 1957, the blue tail light became illegal in almost all states and has remained illegal ever since. That said, you are still very likely to see them if you go to classic or hot-rod car meets. The blue dot modification was popular on everything from hot rods, sedans, motorcycles, trucks, semis, and even trailers.

But before that, the blue dot tail light was first seen in 1933 to 1935 Packards, and it’s assumed the manufacturer invented them. Still, nobody so far can confirm that, and although one might argue that Packards had them from the “factory,” we have to remember that a lot of the Packards at the time were coach-built, so it’s hard to say if that counts. 

Now, as previously stated, the blue dot tail light is just a standard tail light with a round blue lens about an inch in diameter installed in the center. Typically, the blue dot lens is installed directly over the brake light bulb instead of the running lights. That way, the blue dot lens lights up only when you push the brakes.

Considering that all brake lights are red, a brake light with a blue dot lens will become slightly purple/magenta instead of bright red. And while that may look good, the only color a tail light is allowed to be, starting in the late fifties, is red for brake and running lights, white for reverse lights and license plate illumination, and amber for turn signals.

That’s why the blue dot tail light never came standard on any car from the factory and was always an exclusive aftermarket modification. Again, for older cars, you can buy a whole aftermarket tail light with the blue dot pre-installed, but for newer cars, the only way you are getting one is if you buy the blue dot lens and install it yourself.

What Was the Starting Idea Behind Tail Lights with Blue Dot

The initial idea behind these tail lights with blue dot is unknown, just like it’s unknown who invented them or who used them first. Still, that doesn’t stop us from exploring different ideas, most of which came from different forums you can find at the end of this article.

To start, let’s assume that the idea that Packard invented the blue dot lights is true. One gentleman, whose comment you can find here, stated that his theory is that Packard installed the blue dot tail lights on its ’32-’34 V12 models to distinguish it from cheaper models. By this theory, the blue paint dot on tail lights back then were what OLED tail lights are today.

After that theory, let’s assume that the blue dot tail lights have a practical purpose, just like most automotive innovations do, at least initially. My first theory was that blue dot tail lights were the first ever rear fog lights, assuming that blue lights are good at illuminating fog.

However, it’s widely accepted and most likely proven that yellow lights illuminate fog the best, so that theory holds little to no water. That said, one member of the Jalopy Journal forum wrote that his blue dot tail lights broke through fog much better than standard red brake lights. But at this time, there is no way of proving that.

The next theory is very similar to the potential reason Packard had them on their cars, and that’s style. The blue dot, when positioned properly, changes the red brake light hue significantly, making the car stand apart from the crowd.

After that, a lot of car owners who had blue dot tail lights reported that they were significantly brighter than the standard brake lights. Moreover, the round blue dots make a big illuminating corona around each tail light, similar to how people with astigmatism see lights. And, of course, brighter brake lights are never a bad thing.

The next theory doesn’t necessarily explain why blue dot tail lights were invented but rather why they remained popular for so long even though they were not standard equipment. And the theory is that young people loved having blue dots on their cars once they became illegal as a form of teenage rebellion against society, authority, or social norms. In that sense, the blue dots give off the same energy as bosozoku gangs in Japan or, better yet, Japanese teenagers hanging stolen train handles under their cars.

And the last, and my favorite theory, is that initially, blue dot tail lights were something only house call doctors had on their cars, and that way, police could distinguish them from the other drivers and know not to stop them. Once hot rodders and street racers learned about this; they began installing blue dots on their cars to avoid getting pulled over by the police.

But for the time being, all these theories are nothing more than speculation until we find a car enthusiast who lived in those times, which is becoming increasingly difficult as the years go by. Alternatively, we may find something out if someone convinces Roy Gullickson to give him access to the Packard’s archives, but that’s if they still exist.

How Do I Install Blue Dot Tail Lights

The blue dot tail light install is pretty simple. You first need to remove the factory tail light cover from the tail light housing. After that, check where the brake light bulb is located and mark the factory tail light lens in that exact spot. You want the blue dot to be precisely over the brake light bulb for the best effect.

After that, measure the diameter of the blue dot mounting piece. The mounting piece is chrome and goes into the factory tail light. Then, you want to drill in the factory tail light where you previously marked it and make sure it’s the same diameter as the blue dot housing. Also, be careful not to crack the factory lens, and make sure it’s secured to something before you start drilling.

Once you drill the factory tail light, remove any plastic shavings that may have collected on the edges of the hole. Next, insert the blue dot into the tail light hole, and bend the blue dot locking tabs to secure it inside the tail light. Lastly, install the tail light lens, and the job is done.


Q: What do blue dots in tail lights mean?

There is no real meaning behind blue dots in tail lights other than a better aesthetic. And while there is a theory that doctors had blue dots on their cars so that police wouldn’t stop them, that isn’t confirmed by any trustworthy sources.

Q: Are blue dot tail lights legal in Florida?

Yes, blue dot tail lights are legal in Florida but only hot rods or custom-built cars. Those cars must have antique or street rod license plates. In order to get those plates, the car must be at least 25 years old and no older than 1948.

Q: How do you put blue dots in a tail light?

To put blue dots in a tail light, you need to remove the original tail light lens and drill it so that the blue dot lens can fit inside. After that, lock the blue dot in place with its locking tabs. Also, make sure that the blue dot is sitting right in front of the brake light bulb.

Q: Are blue dots legal in Texas?

Blue dots are technically not legal in Texas because all brake lamps in Texas must be red, amber, or any other shade between red and amber. Since blue dot tail lights create a purple light in combination with the factory red lenses that would make them illegal.

Q: Are blue headlights DOT approved?

No, blue headlights, unless they are a factory retrofit, cannot be DOT-approved, even though you may see the DOT approval label on some aftermarket kits. DOT stands for Department of Transportation, which sets requirements for headlights, but does not certify or inspect aftermarket products. So, when you see a DOT-certified headlight kit, it means it meets the DOT requirements but only according to the manufacturer.

Q: Are blue dot tail lights legal in Colorado?

Yes, blue dot tail lights are legal in Colorado, but only if you have street rod license plates. In order to apply for a street rod license plate, your car has to be manufactured in 1948 or earlier.

Q: What do blue lights on a police car mean?

Blue lights on vehicles indicate that the vehicle in question is an emergency or a first responder vehicle. If the lights are on, it means the vehicle, be it an ambulance, police car, or fire engine, is on an emergency call. It also means you should safely move out of the way and let the emergency vehicle through.

Final Words

At the end of the day, we can’t really say for certain where the blue dot lights came from or what their purpose and meaning are, and at this point, it’s highly unlikely that we will ever find out. But the leading theory is that Packard invented the blue dot lights to distinguish their top-of-the-line models and that the trend was carried on well into the 1950s because the lights simply looked cool.

Ibro Cehic

Ever since I was bitten by the automotive bug during early childhood I was obsessed with cars. My first driving experience came when I was ten and I already started tinkering with cars and motorcycles at thirteen. So, right from the beginning, I knew my life would revolve around cars, even if I wasn’t sure how that would happen. And today, thanks to my second passion, writing, I get to share my love for automobiles with other enthusiasts through my articles.

Recent Posts