you have a "current potential" there, might be from moisture on the top of the battery or the corrosion. very rarely is voltage a good check (what ever number you are seeing on the meter is more a function of which cell is shorted to the case, and not how much power could be transfered over that connection). and GE suggests you check Ohms to frame and stop and figure out where a short that has less than 100k ohm before any troubleshooting.
lets make everyone crazy and discuss if the current is coming from the negative to the positive or the other way around...
;-)