A circuit board assembly comprises a circuit board having a connector or contact pad, and a housing. The housing includes a casing having an open end, an end cover sealing the open end of the casing and having a conductor, a coolant inlet for introducing a coolant into the housing, a coolant outlet for discharging the coolant from the housing, an inside connector connected to an inside surface of the conductor of the end cover, and an outside connector connected to an outside surface of conductor. The conductor of the end cover extends from an inside surface of the end cover to an outside surface of the end cover.