The neg/pos thing is in refrence to disconnecting the battery...disconnect the negative cable first...always. No you won't be able to start it if the battery is disconnected
It will probably take two people to run the test unless your meter lead are capable of attaching to the terminals. The voltage might climb a small amount, maybe as high as 14.2vDC. If the regulator is bad in the over charge state you'll see the voltage climbing, if the voltage climbs past 14.2vDC I'd venture to say you've found something.
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Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.