Going to try to explain this....LOL...Need help

No, to check for a draw on the battery, unplug shore power and with that neg wire off the battery, take battery voltage (you got about 12v before, so battery is low) Now attach neg cable and take voltage across battery posts. Any big draw will make that voltage lower than before.

To find out how much draw that is in amps, you need an ammeter, but a muilti-meter usually has a 10a limit and over that will fry it. so with an unknown draw you don't want to find out the hard way it is over 10a :)