Method for monitoring proper fastening of an article of assembly at more than one location

A method for assembling an article of assembly, the article of assembly having a plurality of fastening locations including first and second fastening locations in spaced apart relation, comprising:

• holding the article of assembly in a predetermined position;
• providing a plurality of targets including at least a first target fixed relative to the article of assembly corresponding to the first fastening location of the article of assembly and a second target fixed relative to the article of assembly corresponding to the second fastening location, the second target having a different characteristic than the first target;
• manually fastening fasteners into the article of assembly at the first and second fastening locations;
• and
• sensing the first and second targets when said fastening is occurring at the first and second locations, respectively, and generating an electronic target output based upon said sensing that differentiates between the first and second targets thereby indicating when a fastening tool is in either of the first and second fastening locations.