Everytime I turn my car off the radio presents get erased, so i assume it's reseting my computer. What's up with that?

 

Who ever put in the radio must not have hooked up the constant 12v to a constant source....You have three eccencial wires too hook up on a radio (not including speaker wires) Hot, Ground, and Hot only while the ignition is on....If you hook both Hot wires up to a Fuse that is only hot while the ignition is on then your radio presets are gone ever time, because you don't have any power to the memory