Thanks for the reply mrvett.
I performed the check you outlined above. The most clockwise, the red wire in the plug, shows 12 volts with the switch off and the white wire, least clockwise shows 0 volts with the switch off.
Switch on, both of them show 12 volts.
Switch on, the two wire plug installed into the alternator, battery light on, switch off, battery light off.
Switch on, pull the plug, battery light goes off.
The alternator is a chrome, Powermaster 140 amp 3 wire, internal voltage regulator model.