LED bar graph tach kit?
Ok I really dont need a video. "LEDs dont dim" was a pretty blunt statement.
There are ways to create dimming effects with LED lighting as explored here...
http://www.reuk.co.uk/LED-Dimmer-Circuit.htm
The main reason I steer clear of these sort of things is our application enviroment.
Our classic vehicles electrical can generate spikes from so many different sources that fancy modern electronics never live very long there.
Wrong place for this discussion too, sorry. Good luck