18v25 CS High Power Motor Driver Direction Issue

I am able to drive my motor when the Dir pin is LOW but am unable to drive it in the other direction by setting it high.
Here is the simple code i used.

#define Dir1            13             // Winch 1 Direction Pin
#define PWM1            3                  // PWM motor pin PWMH

void setup() {
  pinMode(Dir1, OUTPUT);
  pinMode(PWM1, OUTPUT);

void loop() {
  digitalWrite(Dir1, HIGH);          
  analogWrite(PWM1, 100);          


Does the ground pin on the arduino need to be connect to ground on the logic side of the board? That is the only thing i can think of doing differently.


Definitely. Your control source and your motor driver have to have a common ground (there has to be a loop for current to circulate). Unless you are doing something rather fancy (e.g. using optocouplers to electrically isolate two systems), establishing a common ground is a general requirement for any two devices/systems you want to connect electrically.

- Ben