It depends on the application. , The first 4 pins on the grey connector are always 1= 12V, 2= GRD, 3= CAN +, and 4= CAN -. , The other pins can be configured however the user wants them to be. , If you have one, and need the pin out, there should be a six digit # starting with 9 on a label on the box. , Get me that number, and I can give you the pin assignments for it.