Have an occasional series of beeps that sound like morse code coming from the area around the interior fusebox, which can be accessed when the driver's door is open, but whenever I've been able to look in there the sound is not active. Is there something electric that quietly chirps in there?

It might be assosiated with the rear window defroster, but I am not sure.

Does it do this all the time?

Maybe remove relay, then see if you hear it! Just a guess! ...---... ...---... its telling you something!