Car tachometer hook up to a pc ?

[Gueza]

Hello everybody
I don't know if this is the right board to post this but anyway..
I have a Golf 3 tachometer taken out of its motherboard(because it's not working anymore) but the tachometer is working, It has 4 connections which I don't know what's their input. the tachometer doesn't have light so the 4 connections could be signal and power.
I've seen several videos before showing PC fan RPM with tachometer and CPU usage with tachometer and I would love to do the same or any other use of the tachometer with my PC since I am a car guy.
I kinda wanted to test the tach with a a 4 cables CPU fan I have, I connected it to a DC 12v and randomly tried to connect it to the tachometer, it either didn't show no signal or the fan slows down while the Tacho shows 2000 rpm but when I slow down the fan with my hand the RPM doesn't change so I think it's just showing voltage.
I kinda suck at programming cards and stuff so an easy hook up would be good.

 

[jitpublisher]

That does require some work, as a tach cannot by its self read or understand the pulse output of a DC fan motor, it takes some translation. Here is a video that may be of help, good luck
https://www.youtube.com/watch?v=66anCxKKiv4

 

[Gueza]

That does require some work, as a tach cannot by its self read or understand the pulse output of a DC fan motor, it takes some translation. Here is a video that may be of help, good luck
https://www.youtube.com/watch?v=66anCxKKiv4

in that video the guy is already using a fan tachometer and he hooked it up to the car tachometer with a transistor, unfortunately there's no information there
If only I could guess what's the 4 connections my tachometer...