What is ?

[Game Over]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Hummer Guy:
Basically it allows you to operate the accessory power ports after the engine is off. Some have auto shut-offs if the battery starts to die. I'm sure some on here can offer a more technical answer if you like. </div></BLOCKQUOTE>

Any answer is good and technical to a newbie like me So basically it's serves as a convenience to do things when engine is off but not necessary ? Reason I am askin is I'm trying to get a wire harness for an aftermarket stereo without having to get the PAC-OS2 module.

Thanks for all your replies