there is loads of posts on this subject,im sure that on the mk2 the unit was moved up under the bulk head,so im assuming you both have the mk1,iirc it controls central locking/alarm and im sure it has been said before that if you catch it in time you can dry the unit out in the airing cupboard,im sure its also been said that someone CAREFULLY drilled some holes so it cannot fill up with water again BUT CHECK THE THREADS BEFORE ATTEMPTING,also mentioned that when putting back put some washers underneath the unit to lift it up a bit,do the research before you go ahead with anything. hth.