I don't know much about the galaxy system but you should be able to check resistance from CAN H to CAN L with the power off and see if you get 120 ohms or 60 ohms. If you get something other then that usually there's a problem. Also make sure the ground you're controller is using to reference CAN voltages is good and a solid connection from controller to the car. Usually the network uses a twisted shielded pair and a lot of people don't hook the shield to ground.
