Closure mechanism for vehicle door

A vehicle door closer mechanism comprising:

• a base member which is fixed to one of a vehicle body and a door which opens and closes an opening of said vehicle body;
• a hook which is provided on said base member and is rotatable between a striker holding position at which said hook is engaged with a striker that is provided on, and projects from, the other of said vehicle body and said door, and a striker releasing position at which said hook is not engaged with said striker;
• a ratchet which is provided on said base member and rotatable between a latching position at which said ratchet is engaged with said hook to hold said hook in said striker holding position and an unlatching position at which said ratchet does not hold said hook in said striker holding position;
• a sector gear which is rotatably supported by said base member and rotates said hook toward said striker holding position by rotating in one direction;
• a pressing member which is provided on and projects from said sector gear;
• a motor which rotates a pinion that is engaged with said sector gear to drive and rotate said sector gear in said one direction;
• and
• a position detection sensor which issues a detection signal by being pressed by said pressing member upon said sector gear being positioned at a predetermined position, said position detection sensor being provided on a facing surface of said base member which faces said sector gear.