The Culprit
This is the reason why you can't open up the Z wiper motor and simply change the position of the stopping/parking position.  Nissan designed "smart" technology into the motor's design.  Without getting into the gory electron details, basically the motor uses whiskers to sense the metal plate on the wheel and parks just off of it.  When the motor becomes energized, it takes off and runs through it's selected cycle, but it always looks for the metal plate before it stops.  The inner wheel will always stop in the position shown.  It even runs backwards once before shutting off.  Pretty clever design that beat me to my wits end before I admitted defeat.  THAT is why you MUST make the modification to the arm if you want the Z motor to work properly in the 510.
 
 
The "whiskers"
The "smart bomb"

 Back to the Z Wiper Modification
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