Nissan Repair: beeping from fusebox, nissan pickup, beepers

Question
So my 94 Nissan pickup has been sitting for about a month.  We went to start it yesterday with no results EXCEPT when the key is in the ignition, the fusebox actually makes a two-tone beeping sound intermittently.  When I pull the ignition lock fuse the sound stops.  Ideas?  Thank you.

Answer
Adam,

Have the battery fully charged and then repeat the process.  I am sure the low voltage is messing with the circuits.  The two beepers are for the seat belt and the door.  If you have one that has the additional one for the lights there would be a ding for that too.