After removing the battery from my 1998 Grand Cherokee, I found what appears to be a pressure switch in the bottom of the battery bracket. Anyone know what this switch does? If it is to detect the presence or absence of the battery, where does it get its energy to indicate anything if the battery is gone. If it is part of the security system, what happens when I replace the battery? The reason I removed the battery and detached the bracket was to gain better access to the alternator.