voltage regulator shorting out in alternator

[Cashflo]

I have had 4 alternators have their voltage regulator short out.
One of the places i got my alternator told me it is a bad ground.
I have checked from each battery with positive disconnected and only one negetive connected at a time and checked the ohms from the battery's negative terminal to the motor(alternator bolt), frame under cab, and body under cab.
All show 0.1 ohm.
Is that the correct procedure?
What next?