jw,
Harbor Freight has multimeters for $2.99 that work great. In fact at that price, I'm going to get more so that I don't have to walk all the way to a different room to use one, (kidding). Just make sure that the meters have a DC amp limit around 10 amps. If they max out in the milliamp range, you will blow fuses with just a 2-3 amp draw. First see how much current (in amps) is flowing from the battery with everything turned off. Then, like the article and everyone here says, go from circuit to circuit to see if there is current flowing, and if so, that it matches the flow you had at the battery. It could be more than one circuit.
