Sounds like a blown strap in the battery, Put your multimeter leads right on the battery lugs not the cable connectors. If it still drops to zero replace the battery, If it doesn't drop to zero clean the battery cable connections.....
Originally Posted by piston slapper
You never learn anything until you admit you don't know it all...
"Why go out preserved when you can go out beat up, worn out, sliding in sideways screaming, Holy Sh!t What A Ride" !!!