There are two main 
fuseboxes fitted to the Scorpio and a selection of relays fitted behind the 
glovebox depending upon features fitted to the particular vehicle. Access to 
these is via a clip down cover inside the glovebox.
The battery side fusebox in particular is prone 
to water damage and MUST be fitted at ALL times with a plastic cover. Failure to 
refit these after servicing WILL result in serious damage - this has happened 
often.
In addition, ensure that the
drain holes are clear.