Abstract: The flow switch assembly (10) of a fluid power apparatus comprises a fluid flow pressure operated switch (10) which activates upon the failure or degradation of fluid flow. A body (14) contains therein a blind bore (15) which receives a piston (71) biased by a spring (17) located at the bottom (13) of the bore (15). A switch housing (11) which is molded about a contact (20) is threadedly inserted into an open threaded end (16) of the bore (15). The bore (15) communicates with a fluid flow opening such that fluid pressure causes the piston (71) to retract against the spring (17). The contact (20) extends axially beyond a wall (11A) of the switch housing (11) such that a radially enlarged portion (21) provides a seat for a seal (30) which sealingly engages the radially enlarged portion (21) and a surface of the bore (15).