Installing LED lights in my Miata

In the 21 years since I purchased my 1993 Mazda Miata, and during the 70,000 miles of driving enjoyment I’ve had behind the wheel, there is one peculiarity that has come to my attention.

The car has shrunk.

Not really. However, the automotive landscape has gone through tremendous upheavals since 1996. When I bought the Miata, from a young woman in her 30s who had purchased it new, I asked her “what will you be replacing it with?” She replied “a Chevy Blazer”. At that point in time, the concept of voluntarily moving from a two-seat sports car to a Sport Utility Vehicle was a foreign one. But no longer. In 2017, the majority of daily-driven vehicles are classified as “light trucks”: minivans, SUVs, and pickup trucks.

The Miata is small even next to the Alfa

It is in that sense that my Miata has gotten smaller, as without exaggeration, every four-wheel contraption sharing pavement with me towers over my windshield. Pulling up next to a late-model Accord or Camry at a stop light is a lesson in relativity, as I observe that those mid-sized sedans’ beltlines are higher than my roof.

As the title of this blog post is “Installing LED lights in my Miata”, you may wonder what the foregoing has to do with LEDs. Plenty, in fact, and it’s summed up in the word conspicuity.

There are two aspects to vehicular lighting, as I was taught in Automotive Safety 101: being able to see, and being seen. Other than headlights, and perhaps reversing lights, a vehicle’s exterior illumination is designed to help other drivers see you. A few weeks ago, it occurred to me that there was a super simple way for me to make the Miata more conspicuous to other drivers, and that would be by installing some LED lights.

To the automotive purists, aftermarket LED lighting may have a bad rap. Your first thought may be of glare-producing headlights (more likely caused by HID lighting). Perhaps you’ve seen some tricked-out show cars with blue/green/violet LED lighting in front and rear lamp assemblies, even under the car, pulsing along with a 120-decibel sound system.

The upgrade I pursued is much more straightforward than that. The aftermarket has made LED light bulbs available, in standard sizes, as “plug-and-play” direct replacements for incandescent bulbs. With the Miata, I wanted to start small, and at the rear, by replacing the combo tail/brake light bulbs (#1157) and reverse bulbs (#1156).

I obtained several sets of bulbs from CARiD.com (and in full disclosure, this is the company where I’m employed). The LED bulbs are available in different colors. I got the 1157 bulbs in both white and red, and the 1156 bulbs in white.

When replacing incandescents with LEDs, it is extremely important that the LED bulb is the same length, or shorter than, the bulb it is replacing. LEDs are available from different companies, and most companies offer them in different lengths. An LED bulb which is too long may not fit at all, or may press against the plastic lens, causing that lens to melt, or worse.

New Lumen LED bulb (right) is slightly shorter than incandescent (left) it’s replacing

My bulbs are the Lumen brand, available in 3 different lengths. Generally speaking, the larger the bulb, the more light it emits. It therefore becomes tempting to decide on the largest bulb; again, make sure that it’s going to fit inside the assembly!

Today’s LEDs are direct replacements, emit lots more light and less heat

In my case, to be on the safe side, I selected the shortest bulbs. With pieces in hand, I opened the Miata’s trunk and was pleasantly surprised to see the covers behind the tail lamp assemblies were easily accessed.

(Sidenote: in 21 years of ownership, I have never removed one of these covers before this LED bulb swap. The ONLY exterior bulb I’ve replaced on this car since 1996 is one sealed-beam headlight bulb. Darn those Japanese, not giving the bulb makers a chance to sell their wares!)

Tail lamp assembly cover easily accessed from trunk

 

Push in two clips, and flip cover (no tools needed)

Once the cover was removed (no need to disconnect the harness plugs), I flipped it over, and both bulbs were right there. I did note that the tail/brake light glass (“envelope” in bulb-speak) was darkened, probably dimming its output; however, the bulbs still worked. Wanting to make changes one step at a time, I swapped out the 1157s first, using the Lumen white LED bulb (the tail lamp housing has a red lens).

To document the changes, I took photos, figuring that the camera doesn’t lie (but it might try to make the car look thinner). I put my Sony digital camera on a tripod, and set the controls to full manual. In this way, the camera’s light sensor would not automatically adjust the exposure, which could artificially make the light look either brighter or darker.

With new tail light bulbs in place, I subjectively thought that the light output was brighter. The big improvement, however, was in the amount of illumination: now, the entire lens assembly was lit, compared to prior, when the upper corners remained dark. So far, so good.

Next to be installed were the reverse lights. This was a great improvement, as the light is not only markedly brighter, the color is a pure white, compared to the hazy yellow of the incandescents.

Lastly, I went back and replaced the 1157 LED white bulbs with the same size in red. My expectations were low, as I had run this same experiment at work several years ago with an older Honda Civic, and the red tail lamp bulbs behind a red lens were not as bright as white bulbs.

The Miata yielded a much better result: the light was slightly brighter, and it was redder too. If conspicuity was my goal, the red 1157s and white 1156s allowed me to achieve it.

(For those who want to make the same upgrades, I would suggest trying both red AND white LED bulbs in the tail lamp assembly – provided that the tail lamp lens is red. Vehicles with WHITE lenses for tail/brake lamps MUST use a red bulb.)

Tail AND brakes lamps both on

What’s next for the Miata’s lighting? I had considered upgrading the front and rear turn signals, but LED bulbs introduce a small hiccup: their low resistance causes the flasher relay in many cars to “hyperflash”, or, flash too rapidly. There is a fix in the way of a resistor, but that costs extra, and must be permanently mounted to the car, a modification that I’m not willing to make.

The front and rear side marker lights would be a likely next step for LEDs. On the interior, the footwell courtesy lighting could really stand to get LEDs (the poor passenger compartment illumination is partly caused by lack of any overhead lights).

Was I surprised by the improvement in the Miata’s rear lighting? Not at all. The biggest surprise may only be that I waited this long to make the upgrades. Oh, and the Alfa will definitely be getting similar LED bulbs. Just don’t tell the AACA judges.

 

All photographs copyright © 2017 Richard A. Reina. Photos may not be copied or reproduced without express written permission.


FUN FACT OF THE WEEK

“Reverse” lights, also known as “back-up” lamps, are wired to illuminate whenever (and only when) the vehicle’s transmission is in reverse. They are designed to both help light the way for the driver, AND, serve as a signal to others of the driver’s intention to move in that direction.
In the U.S., reverse lights became required by law with the passage of the initial Federal Motor Vehicle Safety Standards (FMVSS) in 1968. Before that, back-up lamps were optional equipment for many vehicles, if they were even available. As a boy, I can recall seeing lower-line American cars with steel “blanking plates” in place of reverse lights.