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License plate light LED conversion and dimming

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139
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110
Location
SF Bay Area
#1
Let me start by saying I am an idiot when it comes to electrical circuits and I have no idea if what I did is going to cause issues. But I wanted LED license plate bulbs really bad and I can be a little picky about the color and brightness of my bulbs.

First I installed standard 194 LED bulbs into the factory housings. I was disappointed because one bulb was facing the plate and the other was facing off to the side. So I went back to stock bulbs and started looking for other options. I finally came across an LED setup that replaces the whole housing rather than just the bulb and decided to give them a try. I knew they were going to be way too bright (who uses 18 LEDs for a license plate light?!) but I figured I could work with them. I did some bench testing and found that a 500ohm resistor got me the brightness I was looking for (EDIT: originally I used 1/4W resistors but I'm changing to 1/2W resistors just to be safe). I also left the lights hooked up to 12v on my work bench for a while to make sure nothing was going to overheat. The resistor didn't heat up at all so I figured I was good and soldered them into the lights. So far it's been working fine but it's only been a day. I'm hoping I don't cause any issues with the canbus system.

These are the lights I got:
https://www.aliexpress.com/item/4000287930307.html
64679C88-9FAB-448F-850C-7961AC249D0B.jpeg


First pic is the final result. Second pic shows dimmed light on the left, full brightness on the right. It's so much brighter in person. You can see how it drowns out most of the light from the left side.
IMG_0827.jpeg
IMG_0826.jpeg

And this is how I modified them with a 500ohm 1/4W resistor:
IMG_0822.jpeg
 


Last edited:
OP
bflan2001
Messages
139
Likes
110
Location
SF Bay Area
Thread Starter #3
Just added a link to the post. I got mine from aliexpress but you can find similar pieces on Amazon, eBay, etc.

I'm learning that the 1/4W resistors I used may be too small. I will be replacing them with 1/2W resistors and that should be plenty.
 


Last edited:
OP
bflan2001
Messages
139
Likes
110
Location
SF Bay Area
Thread Starter #5
They use the same type of spring clip as OEM. They fit a little tight so taking them out is tough but overall the fit is good.

The resistors can be purchased individually from electronics suppliers like Mouser or Digikey.

I ordered some more resistors to test, I think a slightly lower ohm would be better but I didn't have anything between 100 and 500. I'll test those in a couple days and report back here.
 


Last edited:

flbchbm

1000 Post Club
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Sterling, VA, USA
#6
I love aliexpress.... all my ST farkles are from ali. Seat gap filler, ST seatbelt cushions, ST center cap covers, metal and abs ST badges in most colors, ST eBrake cover, start button cover (Umbrella corp), ford logo covers, etc.
 




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