An electrical connector assembly includes a housing having an upper housing half removably assembled to a lower housing half via a plurality of fasteners. A circuit board is at least partially disposed in a housing cavity formed by the upper and lower housing halves. The circuit board includes a plurality of conductive front and rear pads electrically connected to each other. Flat cables terminate at the conductive rear pads disposed on upper and lower major surfaces of the circuit board. A plurality of alternating ridges and channels is disposed on a top side of the upper housing half, extending along a length of the housing. Bottom surfaces of the channels along a length of the channels are at a same height or higher than uppermost surfaces of the fasteners in the plurality of fasteners. The channels are configured to transfer heat generated by the connector assembly.