This is an enclosure I made to protect the Sanguinolu circuit board of my Solidoodle 2 and keep all of its wires neatly contained. It flips open for easy full access to the top of the board and contains space for mounting a 12V 40mm fan in the cover.
Print out both pieces with support enabled. Clean both pieces and tap m3 threads into the cover hinge pivots if a tap is available (else just adjust the hole size for a tight fit).
Carefully remove the circuit board from the rear of the printer. If adding a header for a fan, do so at this time. Remount the board on top of the base piece. using m3 screws.
Also use m3 screws to fasten the base piece to the cover at the hinge points. Screw a 40mm fan into the cover and either plug it into an available 12V header in the board or splice into the existing case-light or extruder cooling fan lines.