How to Make an LED Ready to Install Into a Car!


Introduction: How to Make an LED Ready to Install Into a Car!

In this instructable, you will learn how to prep an LED to be ready to install into a car! This means adding a resistor and soldering on some leads. When you are finished, you can do so many things with them and save a few bux too.

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Step 1: Get Your Supplies

You will need wire, an LED and a 560 ohm 1/4 watt resistor.

Step 2: Solder the Resistor

For this step, you will solder the resistor to the longer LED lead, or the anode. This is the positive. The resistor is needed to ensure that the LED only gets 2.5 volts and 20 ma from your cars electrical system.

You will want to trim down the LED and resistors leg so that you don't have a large area of flimsy solder terminals.

When you are finished soldering, slide some shrink tube over the resistor to prevent a short.

Step 3: Solder on Some Leads

Solder on some wire. Make it as long as you want. Use a 18 to 24 gauge wire.

Make sure that you use shrink tube to cover these connections as well. This is also very important.

Also, make sure that you have some indication of positive and negative. I used blue as positive (its all I had on hand) and brown as negative.

Step 4: Install!

Drill some 5mm holes in your car where you would like to mount your LED and run the wires to a switched power source.

Some cars have a switched cigarette socket. In some cars (my case) i borrowed the switched wire from behind the radio. The radio turns off when you shut off the car and the LEDs do the same. If you want to be professional, you could find a blank fuse area and tie in. I opted not to do this...



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    51 Discussions


    It is A LED --- not AN LED

    The AN is uses when there is a vowel in the front, like AN EVENING IN ROMA..


    1 reply

    In English we by convention use "an" in front of vowel *sounds*.

    This is why Brits say "an historical development", since they do not pronounce the "h".

    "LED" is normally pronounced "ell eee dee". It starts with a vowel sound.

    "An" is thus appropriate.


    I was trying to do this but I have no idea on how to hook up it to give the LEDs power. Although I did do a simple circuit with a switch, but it was no big deal, and the connections I made to the 12v lighter jack would not hold to the little clips(soldered). If you can help me out on this I would GREATLY appreciate this!

    My best friend did a similar install but hid a few green LEDs in his air vents it made a nice eerie glow when turned on.

    2 replies

    IM DOIN THAT lol that sounds great! I would put white in my car because I have blue all over the floor, and white in my radio

    Can the resistor be more ohms than it needs to be? My led calls for a 390 ohm resistor when i don't have one!

    3 replies

    You can use a resistor that is higher, just not lower. Use the lowest resistance you have, and if it is not bring enough, you will need to get the proper one. If it is within a couple hundred ohms, you should be ok.

    you can also put in more than one resistor.if u have two 50's they would equal about the same as a 100 or put in enough wire to add up to the correct resistance

    i have a cig jack and i'm trying to put some leds in parallel but as i add more leds the further out ones get dimmer. how can i get around this. also i am putting a resistor on each led and am only trying to use 5 leds

    3 replies

    hmmm - well this sounds like you are using a long piece of wire (maybe 6 feet?) and the resistance is adding up causing the LEDs further down the line to get less current. You may want to consider using a heavier gauge wire The other option is to adjust your resistors. If there is 50 ohms of resistance in the wire up to the LED, subtract that from your resistor value (if you calculated a 560 ohm resistor, then you could get 510 ohms) LEDs have a brightness vs. current graph that is almost exponential, so even a 1 mA drop in current makes a huge difference (especially in the lower currents less than 20 mA)

    there is no wire going in between each led. they r soldered directly to each other. i tried doing the same process accept with only one resistor on the first led. this worked ok but i don't know if this would shorten the life of the led or not. i dont know if i made this clear or not but theleds as a whole r not getting dimmer but instead it kinda goes like this.


    nice, but i was wondering if its possible to wire it up to the interior overhead light wires, and put it up in the headliner, so it only comes on when a door is opened....and maybe in otherplaces as well, but ONLY when the door opens

    3 replies

    Absolutely! You simply have to source the wires coming from the dome light. It will only work when the dome light switch is activated or the doors are open.

    i could wire them to my head lights for clearance lights on my motorhome.which in my state have no regulation on them.

    could i possibly take out the main overhead light and use the wire ends from there? all i have for an interior is a single bench seat and no more room, so bright leds will be enough......

    if you are doing a string of about 20, does each LED need a resistor on it?

    if you are doing a string of about 20, does each LED need a resistor on it?