The other day, while parking my car in the apartment, the anti-theft alarm suddenly started blaring nonstop.
While searching for the cause...
It turns out that if the car key button is broken and keeps being pressed, the alarm may continue to sound.
When I contacted a place that makes car keys, they said the SM3 2010 model key is discontinued...
They quoted a repair cost of 50,000 won but can't guarantee if they can fix the key.
So I decided to try fixing it myself.
-The person who messed up an iPhone 7 repair-
1. Disassembling the Car Key
First, I opened the car key and found that the car's lock button was wrecked inside.
The lock button was hard to press, so I always pressed it hard...
Looking closely at the button, it seemed that there was a metal plate in the center that, when pressed by the button above it, connected both sides of the circuit.


After some research, I found out that the button is called a micro tactile switch. It's easy to find the structure of a micro tactile switch.
It acts as the middle part connecting two circuits.
The round metal plate on top was completely stuck to the switch, continually completing the circuit!
After bending the plate away and pressing the button, it worked well.
I decided to just replace the switch.
2. Purchasing Parts and Soldering


I bought a total of 10 micro tactile switches for 7,000 won including shipping.
I bought a soldering iron at Daiso for 5,000 won...
Couldn't buy solder because the hardware store was closed, planning to get it next time.
It seemed possible to attach it with just the solder left on the existing board.


After placing the new micro tactile switch on the original button position of the car key board and applying heat with a soldering iron, it quickly bonded.
After assembling the car key and testing it, there were no issues. It seems it will work fine for a while.

3. Reinforcing the Car Key
I thought I had fixed the SM3 car key button...
But now the lock button is broken.
So I decided to replace the entire button and switch the rubber with leather.
Button replacement was done the same way as before, adding a bit more solder to secure it.
The button pressed well.


Changing rubber pads for the SM3 evokes a sense of frustration.
No matter how hard you look, there's no rubber pad for the SM3.
So, I decided to make it out of leather instead.
Since it's low power, there shouldn't be any risk of the leather catching fire, and leather itself is an insulator, so it should be fine.
As long as it doesn't get wet, haha.
I made a template for the leather to replace the worn rubber.
It seemed necessary for the top part to be slightly firm, so I used reinforcement materials and planned to attach both the reinforcement materials and Pueblo for the buttons.


If there's one mistake I made...
I should have used soft leather for the top.
Because when the switch is pressed, the top needs to be soft, so other keys aren't pressed together.
Although the reinforcement material was thin, making it hard for other keys to be pressed, it felt a bit stiff.

This created a unique car key with Pueblo leather buttons.
The keys press very well.
However, it seems like the leather might wear with continuous pressing, so I'll have to make a key case next time.
4. Car Key Repair Review
I wrote this on Naver on October 3, 2020.
As of September 1, 2021, the car key has been working without any problems.
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