Speedometer pins problem

Hello Here is the initial post on the forum FR: http://forum.arduino.cc/index.php? Topic=405132.0. The images posted above can largely help you to understand better my problem. I had difficulty understanding first of all the plan stuck above, but in the end I managed to connect all the pins A, and thus managed to light bulbs, clock as well as meter.
My problem is now being able to move the needle of the stepper motor gauge. Thus I went on this Web page: http://www.siak.biz/en/analogue_tachographs.ht m, in the hope that by sending them an e-mail, they could answer me.

But not at all! It is going to make more than a week than I sent to them, and no answer:/Here is my problem expressed in the e-mail, I hope to be more fortunate than on the forum Rr ^^ ' Always no answer, on the other hand I managed to connect the stepper motor gauge. Here is moreover the model: http://www.speedometermotors.com/products/vdo-mercedes-volkswagen-stepper-motor-gauge -91-255-002.
I took pins B2, B3, B8 and D3, because every time I test the current which passes with the multimeter between these pins and 4 pins of the stepper motor gauge, he always indicates to me of the current which passes, while the remaining pins of the tacho, them, always leave one 1 posted with the screen. Thus I threw a sketch arduino basic to move the needle: https://arduining.com/2012/04/22/arduino-drivin g-a-micro-stepper-motor.
Given that I have no potentiometer, I cannot use(get) the loop method, however, it looks like 2 lines in the setup() function, move a little the needle.
In brief I need your help, as I did not find a datasheet for the stepper motor gauge, could provide myself to me a code to make out a will if it work. I connected his 4 pins with pins digitales of my arduino, it is what it was necessary to make, nan?

Thank you in advance =)

PS = Sorry for the bad translation, i'm french and reverso is my only hope to contact you about my problem :slight_smile: