These controlers are designed to work with a LCD. We've had several instances on this forum where people tried to run without the LCD, but they encountered problems with speed limits and power because without the LCD, you can't adjust the settings.
There's one thing that worries me. You called it a KU36, which implies 36v, yet you have a 48bv battery! The LCD would show an error code if something was wrong, like wrong voltage battery. Do you have the LCD?