Okay, lots of cars these days have red LED taillights, and plans are in place to use white LEDs as headlights, but I’ve not seen anyone selling kits to convert the existing taillights of cars to LEDs. Why is that? I know it wouldn’t be cheap, but since LEDs have a long life and respond faster than regular lights, you’d think that someone out there would have such a kit. Anyone know why not?
I’ve seen LED bulb replacements. Just some little thing that fits in a usual light socket and has a bunch of LEDs on it.
Part of the problem of converting is that LEDs are quite directional and so they don’t work very well in a reflector dish. Purpose-built LED tail lights typically overcome this by using a grid of emitters that spans the entire area of the lens, but this means they have to be tailor-made for the shape of the tail light for the particular model of car.
I’m pretty sure the LED replacement lamps will only produce something that looks like like a bright spot in the centre of an otherwise poorly lit lens/cover - this is OK if the total area is relatively small (as is the case with many motorcycles), but it will probably not look so good (quite aside from possibly failing to meet safety standards) on some modern cars with large tail light arrays.
I saw a Civic yesterday with what appeared to be LED taillights. The lens cover was clear, on each side there was one large red cluster and three smaller red clusters, plus a small white cluster. The large one was brake lights, one of the small red ones was the turn signal, the white one (I assume, as I didn’t see it come on at all) was back up lights, and (again assuming since the headlights weren’t on) the other two red ones were taillights. The car was a few years old, so they must have been an aftermarket “upgrade,” but I didn’t pull up next to the guy to find out where he got them. Looked really ugly IMO, but to each his own.
I purchased a set of 1157-style LED stop bulbs from a tiny local store that sells dress up stuff, primarily for import cars. They sit on my desk because they were dangerously dissapointing in terms of visibility. As Mangetout said, they looked like a dim red spot in the middle of a red lens. No way would I run these in my car for real. They might make good front turn-signals, but the red lamp under orange lens looks ugly. I have yet to find amber LEDs in a 1156 assembly. Ooo… or maybe white ones…
Still wanting LEDs to be involved somehow with my braking indicators, I turned my eye to the high-mount stop lamp and using rotary cutting tool, soldering iron, PCB etch kit, some big-watt resistors and very high intensity red LED’s from an electronics supply shop, I made my own grid of about 16 1/4" LEDs. Since the HMSL on a 1992 Honda Civic didn’t even use a reflector, they worked very well until the car was totaled by an idiot in an SUV.
The LEDs reached full brightness noticably quicker than the incandescents, which is what I wanted, and I could be reasonably assured that the LEDs would last years beyond any filament bulb so I would always have at least one brake indicator.
If someone started making replacement lamp assemblies for my car, I’d be all over them. I’d love brake lamps that looks like the new Cadillac’s. Mmmm.
So how often do you have to replace a taillight? Maybe once during the life of a car? This seems to be a solution in search of a problem.
You’re joking; I reckon I change a brake light about once every 9 months or less.
I think I had to change one taillight in my past three cars. Perhaps I just don’t use the brakes as much as you do. 
There might be other factors; local weather, bumpy roads etc.
My guess is that the primary reason you’re not seeing many after-market kits is due to safety rules set forth by the Department of Transportation (at least in the U.S.). The DOT has strict rules governing many technical aspects of vehicle lighting, including beam width, brightness, color, reflectance, etc. Any after-market kit would have to conform to these requirements.
That’s bizarre. I haven’t changed a bulb in a car since about 1987. What are you driving?
May as well answer the OP while I’m here, too.
Look here:
http://www.lightlens.com/coloredbulbs.htm
There’s all kinds of colors, shapes and sizes. They’re plug-in replacements for incandescent bulbs.
Doesn’t seem to matter what I drive; the same thing has happened in every car I’ve had (Renault 6, Ford Fiesta, Citroen 2CV, Austin Ambassador, Mini Metro, Vauxhall Nova & Astra, Fiat Scudo) - they were all the same. It wasn’t just brake lights either - headlamps and indicators too. Perhaps it is something to do with the way that street lamps never turn off when I walk by.
Just had a thought: There is a way to make a kit so one could have LED taillights in their car, without it being custom designed! DOT regulations require the light to be a certain size, so that would be the “bulb,” around it would be a grid that can be easily trimmed to fit the taillight opening. The LED’s would be mounted in a set up similar to indoor Christmas tree lights. You then plug the LEDs into the grid, thus giving you ample lighting in your taillights. Plus, you could put custom messages in your taillights like Stop! Asshole!
I’d wager that the first “asshole” to stop, would be the cop pulling you over for broadcasting an offensive message. Many years ago, someone designed a “Times Square” style display for a car’s rear window. They were obliged to specifically block all cuss words from being shown.
No doubt. But I also don’t doubt that someone’ll try that. Nothing like broadcasting “I’m stupid!” Ya know? The guy’ll probably have some drugs on him when the cops pull him over, as well. 
On this note, how impressed are people with the reliability of these taillights? I’ve seen a couple $40,000 cars with them, maybe only a year or two old, that already have burnt-out LED’s. That must suck - or do you easily (and cheaply) replace the whole unit?
On the incandescent note - I’ve likely replaced only one light in maybe 8 years.
It certainly isn’t the LEDs burning out that quickly. A typical LED has a 100,000-hour average life. One of thwo things is happening there: 1) crappy solder joints are failing, or 2) shock and vibration are somehow causing the LED to fail mechanically.
- is certainly possible.
- is unlikely, they’re encapsulated.
There are other possibilities:
- The LED’s were driven too close to their thermal limits.
- The current limiting devices (resistors or transistor arrays) were driven too close to their thermal limits.
Just comes down to poor design, which should work itself out in the next generation.
I can’t imagine any engineer designing that close to tolerance. Then again, the company management has the final say in the product specs, and I’ve certainly seen the advice of engineers totally ignored in favor of a cheaper, but more failure-prone design. OTOH, I’ve only been involved with engineering for military and government specs. I can imagine commercial engineering is a bit, shall we say, looser.