Hello, First a bit of background on what I have and what I have conected: Arduino Uno, 4x4 chasis with 4 motors and 5x1.5V battery holder, 2 pololu high power motor drivers 36v9(http://www.pololu.com/catalog/product/756) Even thought it is soposed to be 4x4 and 4 motors, I have it conected so that one motor driver drives the left side and the other the right side, making it more caterpillar like. Putting direct power to the conections it all works as planned. The problem arrises once it is all conected and I try out my program. I am not sure if it is a software or a hardware problem. The conections I have at the momment are very simple, positive from the batteries going to the Vin pin of the arduino and the V+ of the motor drivers, negative to the gnd pin next to Vin pin, and to the GND pin of the drivers, then I have motor outputs to the OUTA and OUTB of the motor drivers. Now all I want is to be able to test the motor drivers with a PWM before I keep on with the rest of my project. But so far I have tried almost all the posible things I can think of looking at datasheets and what I have seen on the forum that I think could have provided me with a suitable pwm. Now I think that all I need is to set a digital pin to H for the direction pin of the motor driver, and then send it a PWM to the pwm pin of the motor driver. And as I say, so far I have not been able to acomplish anything,I keep uploading diferent versions of code, and all it does in blink the led closest to the 13 pin quickly about 3 times and stops. I'm sure it is something stupid, and that I am doing something silly wrong. Maybe not uploading the code properly or not making the right conections. I can put up code and a wiring diagram I am trying to use if needed. Thank you all in advance for any posible answers.