Chuck,
I agree with Pat, take the + wire and hook to +. Take the other and hook it to - or l. Then watch it work, or get ready to arc weld
Just kidding. Do a quick turn of the key or whatever you use to trigger voltmeter, worst case should spike in reverse and then correct wires. I have traced essentially all the wires on mine if you want to call me for the colors of my voltmeter wires, feel free. Excelguru knows how to get me live in case you don't.