Quick answer to #2. Yes, the drive is a DC motor
. 12V applied in one polarity causes the motor
to turn one way. 12V applied in the other polarity causes the motor to turn the other way. I proved this one time when I had a problem with mine. I found the quick connect where the 12V is brought to the motor and unplugged it. I forced a small wire in each side and plugged it back in, then brought the wire out to the cockpit
for easy access with a voltmeter. I watched the DC polarity reverse each time the authhelm called for a correction. The motor then hit the dead spot I was looking for and even though the computer was calling for a correction the motor did nothing! Time to have the motor rebuilt!