[Solved] Wind simulator all or nothing

Hello, since 2 days i try to make a wind simulator with:

-an Elegoo uno r3 (i tryed 2 different)

-an adafruit Motor Shield v2.3 (i also tryed with a DK Motor Shield)

-1 fan DC 12V 1.40A 4000Rpm (i also tryed basic 12v motor)

-my power supply is a 12V 2A

So when i test the fan on the static wind section it works on all or nothing whatever if i change the percentage of the global/the effect/or motor section, it stop at 0% end go at full power when i reach 1% to 100% i also try with the speed effect in Iracing and it's the same when i reach the minimum speed.

So if anyone had a sugestion because i am totally lost

Thank you

Excuse my poor English