intermittent problems can be a real challenge.
first thought is that something else is on the circuit that is causing the problem. do u loose anything else? the air conditioner, hood fan (if urs is 12v), light, tv amplifier...
does it happen when u open the door...that could be a problem with the frig light.
i am assuming that it is the dc fuse blowing. i'm purposely trying to stay away form a problem with the frig because the control board also has fuses and i would think they would go first.
when i looked at fuse layout for mine, it appears the frig is the only thing on there. if that is the case, i would try wiggling the (12 volt supply) wire at each end (where it connects at the frig and where it connects to the fuse) and see if u can recreate the problem.
check the screws on the connections and see if they are tight (this is what i call picking at straws).
i know this really doesn't tell u anything but let us know how u turn out.