Quote Originally Posted by jville95
But even with that, that would reset all your radio stations, clock, etc. in your car.
You can wire up a 9v battery to a lighter socket 12v accessory plug (from an old phone charger or whatever) and that will give you enough power to keep the memory in your stereo and clock but not enough for a theif to crank the car.

You can get the parts to make one including the 12v plug, the battery, and the the plug for the battery at Radio Shack for less than $10. Good thing to have if you take out your battery a lot.