As far as I am aware, the only time you can 'fry' a fuse box is if you
replace the front interior light with an LED type with the door open
(making a circuit). I have knowledge of 2x 454's that have done this,
one a Brabus and the other a CDi.
There is a possibility that one of the fuses on the battery post plate
has blown, but really I think that no one should consider adding any
post/s with comments or suggestions until the owner has replaced
the dead battery, and then seen if there are still problems or issues.
OK ?