LED Tail lights Write Up

[patrickleslie]

This thread is xA6x specific but the method will work for most '80s Toyotas of similar tail light construction.

There aren't many aftermarket tail lights available at any reasonable price for the xA6x Celica/Supra, so I decided to make my own. Before I did this I read up the laws and ADRs, as long as you use the same lenses then the only law that you could possibly contradict would be the brightness of the light emitted. You are, in legal terms, just changing the bulbs . I checked this out mathematically and went overboard, the figures say that this particular set up is twice as bright as just the standard globes and is visible at the required distances and angles. That will of course depend on how many LEDS you use.

Tail lights:

Tail and brake lights:



What you need:
- Blank circuit board of similar size to your tail lights. Larger is better, you can always cut it down to fit perfectly.
- Copious amounts of LEDS, RED, ORANGE and WHITE for brake, indicator and reverse. Enough for both sides. Don't just get white LEDs and rely on the lense for the colour, it looks better with the correct colour LED in the first place. And make sure they are actually coloured LEDs and not just white with a tinted shroud.
- Resistors!
- Hot glue gun
- Silicone glue for the lense.

[patrickleslie]

STEP ONE: BUY MATERIALS

Choose your LEDS. I tried to pick some with similar specs but the specs depend on the colour so dont bother too much with that. Get more Red ones than white or Orange as you'll use way more of them.
These are the exact ones I bought:

100 5mm 2 Pin Round White LED Light Emitting Diode Lamp | eBay
100 5mm Ultra Bright Red 6000 mcd LED Bulb Light lamp | eBay
100 x 5mm Ultra Bright Orange 6000 mcd LED Bulb Light | eBay

Note that they are all 20mA max continuous current.
Then, run them through this wizard so you can work out what resistors to get:

LED series parallel array wizard

I worked off a car having 12V. Just have a play around, put your maximum values in, mess with the size of the array, you'll see how it works. What you are aiming for is one resistor size that you can use for all your LEDs. If memory serves, knowing the the electrical margins and the fact that they aren't on all the time for long periods of time I think I ended up choosing 150ohm resistors for the whole thing as a cost saving measure so I would only have to buy one type of resistor. It would probably be smarter and better if you choose individual resistors for individual LED types, but it's up to you!

You are aiming for an array which is a single row array which uses however many LEDs as you input and where there is only 1 resistor.

This meant my array would be the following:
4x Red LEDs to 1x 150ohm resistor
4x Orange LEDs to 1x 150ohm resistor
3x White LEDs to 1x 150ohm resistor OR 4x White LEDs with no resistor.

At this stage, look around the same eBay stores and try to get a blank circuit board from them too to save on postage
My total here was less than $25 AUS.


EDIT: See image about 10 posts below, I used 14.2 as the voltage and I chose 330ohm resistors for the red and orange 4:1, and 120ohm resistors for the whites 4:1. Turns out my memory is not so good...

[patrickleslie]

STEP TWO: SEPARATE YOUR TAIL LIGHTS

This is easier to explain with pictures, so scroll down...

First take them out of the car and remove any plastic garnish and electrics. They should just be clipped or screwed on, it's easy.


Then examine the glue between the coloured lense and the plastic backing. You are checking for major cracks or problem spots to be aware of before you start:


In the bath or laundry sink, soak the thing in boiling hot water to soften the glue. DO NOT EVEN THINK ABOUT PUTTING THIS IN THE OVEN TO HEAT IT UP:


Take a fine sharp knife and slice into the now looser glue. You are not trying to cut it out, just trying to weaken the glue:


After you have sliced all the way around it's back to the sink for more water plumbed straight from the depths of hell:


Let it soak in the heat for a long time, go have some yoghurt and a coffee:


Back at the sink, the glue should look something like this now:


Slice around again, and you should be able to pry it open like this. If not, repeat soaking in boiling water until this is easy:


Patience is essential. Just keep boiling it until this happens easily. You do NOT want to crack anything.


Then scrape around with a knife and get all that excess glue off while it's still soft. Throw away that clear lense between the grey plastic and the coloured lense. It's there to 'focus' the light from the bulbs to all corners of the exterior lense, since you wont have bulbs anymore you won't be needing it. Plus it gets in the way.

[patrickleslie]

STEP THREE: CUT CIRCUIT BOARD TO SIZE AND DESIGN YOUR LEDs

Easy.
Cut the board so it will fit in as flat a manner as possible. When designing your pattern it is best to sit the LEDs in the holes so you can physically see what lines up where and you can get an idea of the clearance at the back.




Your pattern must relate to the LED array you worked out in step one. If you have 4x LEDs to one resistor then your pattern will need to have a total number of LEDs as a multiple of 4.

Play around with it, I had a couple of tries before I found one that I liked. Once you have chosen a pattern, remove each LED one by one and mark the exact holes that it used on the board. This will make it SO much easier to put together later.

Now unless you are a genius you will struggle to get the LEDs to change brightness between tail lights and brake lights. Take a look a the bulb sockets, there are clearly two positive ends and one negative end, for the dual filament bulb. See, even Toyota cheated and they don't know how to make the one thing shine at two brightnessessess (wut even words?). What you have to do is make your design a two stage design where some LEDS will light up for the tail lights and some for the brake lights and tap into those two distinct positive wires of the factory light loom.

[patrickleslie]

STEP FOUR: HOT GLUE AND SOLDER

Now, I know I probably shouldn't have soldered, it can get brittle and break with the vibrations in the car. You can protect against that with heat shrink but that's a pain in the arse. If you are rich you can take you circuit board design from step three and get a printed circuit board where all you have to do is solder the LEDs and Resistors to the board and not to themselves, that would be the ideal way to go. But pfft, who does things the easy way!

Put a dab of hot glue on the base of the LED and slip it into the holes you marked out before. When you have put 4 in (or however may your array defines), flip the board and solder the LEDs in series with a Resistor on the end.


Sorry for the blurry photo, it's the only one I have of the middle of this process.

LEDs HAVE A POSITIVE AND A NEGATIVE SIDE. The difference is that the positive pin is longer than the negative pin. YOU MUST GET THIS RIGHT.
Resistors work both ways. and go better on the negative end of the series. You should end up with a loose positive LED end, with 4 LEDs joined neg-to-pos in series and the resistor on the negative end of the last LED with a loose end on the other side of the resistor.

What you then do is collect all the positive ends together and all the negative ends together to create a parallel circuit where each 4 LED + 1 Resistor is a part of. Add wires so you can tap into the existing factory clips.



After you have done that, note the pos and neg sides and then cut your bulb sockets off the wires and stick your LED wires onto the factory wires.

[patrickleslie]

STEP FIVE: TEST

Do not glue your lense back on with silicone yet, just sit it in there. I made one at a time so the following are comparisons between factory on the left and LED on the right.

It's good to test parts of the circuit at a time too:


Tail lights only:


Tail lights only:


Brake lights and tail lights:

Trust me, the LEDs are alot brighter, this photo is just shit



Note that the LEDs respond immediately and the bulbs take a little while to catch up.

[patrickleslie]

STEP SIX: SILICONE GLUE IT UP

Once you are happy with your LEDs and how they are working, silicone tack the circuit board directly onto the grey plastic then put a bead in the grey plastic and put the lense back, then fit to the car = win.







All these pics are of the lights in my SA63.
You may notice, I never actually did the reverse light or indicators...well...I kinda got myself into a rush and needed the car drivable by a certain time and only did the red LEDs! You can thank my girlfriend for that

I got a bit lazy and never went back to finish the job, but I do plan on redoing these in the near future so I can have a better set to go in my MA61

[river]

Hi,

Nice work and good write up.

Not so sure about running the 4 LEDs without a resistor. How does it not blow the LEDs without some form of current limit which the resistor provides?

If you got a lot of LEDs to run you can parallel strings of them with a resistor per string.

Doesn't the bokka (indicator flasher) go funny with LEDs cos it reduces the load at it doesn't flash properly?

seeyuzz
river

[patrickleslie]

The LEDs have a certain amount of resitance themselves, if you run enough of them you won't need a resistor at all
That's eactly what I did River, parallel strings, spot on! I'll try to find a pic of my original diagram that has all the maths on it
And yes the flasher does go crazy with LEDs because it reduces the load. That's easy to fix in theory, just add more 'load' (resistors) before the LED circuit. You would probably have to test with a multimeter to get it exactly right. I'll update the thread on this when I complete the set for my MA61 which will have LEDs for brake, tail, indicator and reverse

[JadeEstevez]

You can buy Resistors from Autoparts stores specially to fix the spazzy indicator problem. I have a few of them as I plan on doing this at some stage... When I have money

[BEVANI]

nice writeup!

with the large board the LED setup is almost endless so you could have them round or square or anything you want!
another thing to add to the list of little things to do on a rainy day!

Good job!

[litldv8]

you can get a flasher can to suit led lights

[patrickleslie]

That's my final calculations, turns out my memory is not so good

[patrickleslie]

LED tails lights on MK3 Toyota Supra MKIII - YouTube
LED JDM tail lights are finished! Lots of photos

Here's some in a MkIII Supra

[zahmad]

Great guide and future reference material!
Thanks!