I fly out of Tucson and had over-heat problems with my ICOM radio and Grand Rapids HX MFD.  I tried all kinds of fans, but at best you're just replacing real hot avionics compartment air with hot cabin air so I got rid of the fans and ducted outside air to the back of the panel.  I replaced the right wing attach bolt access panel with a small scoop, channeling air through the leading edge of the wing, put a fitting and ducting from the access panel at the copilot's feet to the back of the instrument panel.  So far everything is running cool--it was 113 on the ramp and 95 @7000' yesterday.