Connector assembly with mechanism for confirmation of fitting of connector housing and method of attaching connector housing

A connector assembly comprising:

• a first housing in which an end of at least one first signal line is attached, and which has a fitting opening and a detection insertion opening formed at a side;
• a second housing in which an end of at least one second line to be connected to the end of said first signal line is attached and which fits into said fitting opening of the first housing;
• and
• a plate shaped fitting detection pin which is inserted into said detection insertion opening so as to pass through an approximate center axis of the first housing,
• said second housing being formed with a detection pin recess which allows the insertion of said fitting detection pin in a state where said second housing is fitted into said fitting opening of said first housing,
• said detection pin recess comprising facing inner walls, at least one of said inner walls being formed with a projection guide rib,
• cam grooves formed on opposite sides of said detection pin, said cam grooves having slanted walls constituted so that in a state where said fitting detection pin is inserted into said detection insertion opening, a front end of said projection guide rib engages with said fitting detection pin, such that a force acts in a direction pushing said second housing into said fitting opening of said first housing as said fitting detection pin is inserted into said detection insertion opening, wherein two sides of said detection insertion opening formed at a side of said first housing are formed with panel fixing lock pieces for attaching and affixing said first housing in a panel hole formed in a panel.