Boot lock releases randomly, pls. help!!

[Forester2009]

Hi Fellows,

I own a 2009 Forester. A couple of days ago while driving on a motorway my boot's lock released automatically (did not open the boot phisically but it got loose) - managed to lock it, although, when I started the engine it released again...tried to lock again with no succes, then managed to lock again somehow, although it has gone off again in a few seconds...had no choice but to drive like this with the lights showing an open door on. drove to the nearest subaru garage, they checked and said that the lock itself, the microchip and also the cables are all OK, they have no clue what could have caused it. They have deconnected the lock and the controller chip and now it is locked and can only be opened from inside the boot.

I took it to another garage today where they had no success again and they just simply have no idea what could cause the problem and how can it be fixed (even some of my hard headed subaru expert friends have no clue...) 

Unfortunately outside of and far from UK so I would need an advice, instead of a garage suggestion. Any help would be greatly appreciated! Thanks a lot! 

[Gaulson]

Is it an electronic boot lock? It could be a dodgy earth causing it to short and release.

[Forester2009]

Yes, it is an electronic lock. The fuses have been checked and all seem to be OK! The electrician guy at the garage said that the lock works so he can't see any hardware problems although it might gets a wrong sign or something...