Hello, I have recently purchased an ampline mrd m301 but at the moment i dont have a car to put it in, i am a bit worried though as i wired up the remote wire and positive and ground off a 12v battery in my house just to get a reading of 12v on the display however it didnt display anything is this because its faulty or is it because iv more than likely that the speaker output/input were not plugged in? Thankyou very much James