A motor vehicle as a mobile unit mounts various electronic instruments. The motor vehicle mounts a wiring harness to transmit electric power and control signals to the electronic instruments. The wiring harness includes a plurality of electric wires and connectors. The electric wire is a so-called coated electric wire, which includes an electrically conductive core wire and an electrically insulating coating which coats the core wire.
As the connector described above, for example, a connector disclosed in Japanese Patent Application Laid-Open No. H5-152028 is used. The connector disclosed in Japanese Patent Application Laid-Open No. H5-152028 includes a connector housing, a mat seal and so on. The connector housing includes a tube-shaped outer case and an inner housing, which is received in and attached to the outer case. The inner housing receives terminal fittings attached to ends of electric wires.
The mat seal is made of resilient synthetic resin such as rubber and formed in a thick flat plate-shape. The mat seal is provided with a plurality of holes, through which the electric wires pass. The mat seal allows the electric wires to pass through the holes and is received in the outer housing, so that the mat seal maintains a watertight characteristic between the electric wires and outer housing, that is, between the electric wires and the connector housing.
The connector described above is assembled as follows. The outer housing and the inner housing are assembled to each other, the electric wires attached to the terminal fittings are allowed to pass through the respective holes of the mat seal, and the mat seal is press-fit into the outer housing. Thus, the connector having a structure described above is assembled and fit to a mating connector. As for thus assembled connector, the mat seal maintains a watertight characteristic between the electric wires and the outer housing, that is, between the electric wires and the connector housing so as to prevent liquid such as water from entering the connector housing along the electric wires.