Showroom IL2 Sim on 2 Dof

can´t watch the video "Video Unavailable".
when you can manipulate the green line from both motors in SMC, the error must be somewhere else.
My guess:
-you did the wiring between arduino and monsters schield wrong or the cables have a bad connection.
-the motor shield is broken
-the motor is broken

EDIT: there is a led on both outputs on the motor shield. when the motor shield tries to give an output that leds should shine.

I checked the wiring with a meter today.
All soldered joints are OK Arduino and SMC3 communication is also OK.
Arduino and SMC3 have been displaced according to @eaorobbie's plan.

I also bought a multimeter.

When measuring SCM3, 12 volts are present but no output.
LED is always lit with 0 volts on both outputs, I suspect the SMC is defective, unfortunately it is one from sparkfun.com.

SCM

so have the MMs neu verdrate according to plan more power, at the beginning I had zero volts at both ausgenge A1 A2 or B1 B2, after several attempts and prüfüngen I wanted to stop further,
but then after switching off the SMC3 Uti. program, an LED lit up for a short time.
So I put my voltage back on and look, at both outputs 11.85 volts test motor is connected and it starts to turn until I turn the potentiometer, at the output A1-A2 it can be fast but when turning back the potentiometer the motor stops and does not start anymore, I have to switch off the SMC3 Uti. program and restart it. I have to switch off the program SMC3 Uti. and restart it then the motor turns fully on, I change to B1-B2 the motor turns when I turn the potentiometer full power to the right and when I turn back the potentiometer it turns to the left which it does not do at A1-A2, but I have to switch on and off the SMC3 program again and again otherwise nothing works, I have made a couple of pictures and attach them.
Translated with www.DeepL.com/Translator (free version)

after rewiring, Podi test

Tension applied and measurement

After switching off the SMC3 programme
LED lights up from motor output

after the test of @SilentChill with multimeter
could determine that the MMs is defective because A1-A2 can not be controlled with the Podi

if the green line is exactly on the blue line the motor will stop. if you cross that line, the motor will change direction.
if you cross the red line, the motor turn off and you have to bring the green line back between the red lines and click on "off" to turn the motors back on.
The blue line is the position your motor tries to get
The red line is emergency shutdown to prevent your rig from getting damaged.
If the motor runs wild on A , you need to swap + und - .

it does exactly as you described it stops at the blue line and it also changes the rotation
and at the red line it turns off and when I turn the podi back and press on it turns on again

how do i get the connection with simtools now?
have turned everything on and run the game LVS but nothing happens

does anyone have a wiring diagram on how to connect 2 motors?

change "comport" to the one your arduino uses. you should connect the potentiometer with the motor first or it will spin endless in one direction, like it does now.

with a different motor driver?

have taken over your data, Aduino and SMC both switched to com 1 in simtools com 1 set unfortunately no movement

have read that with LFS you have to run a race in first person mode before you can patch it for movement.
as this generates some required files
did the race and patched LFS also nothing