Any drain on a battery for a long period of time will drain your system. Even your radar detector will do it. Even an aftermarket anti-theft system will do the same thing. It needs to get the power some how. Luckly its an easy fix, just unplug your detector and keep on parkin. My truck sat for a few months w/o the batteries hooked up and I plugged them in and it fired right up. I have the NeverStarts from WalMart. They were in there when I got the truck.