A grommet assembly includes a wire harness and a grommet including a hollow channel configured to receive the wire harness therein. At least one rib extends inwards from and substantially annularly about the interior surface of the hollow channel. At least one port configured to fluidly couple the hollow channel with an exterior environment is defined by the grommet. Material is injected into the channel through the port to secure the grommet relative to the wire harness. The material injected into the channel flows through interstices located between adjacent wires that define the wire harness so as to encapsulate the wires. The injected material also flows into other voids and openings located within the hollow channel. Upon setting, the injected material is configured to prevent movement of the grommet relative to the wire harness and to prevent the passage of contaminants through the grommet assembly.