OK so I believe I've traced a drain down to the fuse that handles dome lights, speedometer, chime/buzzer.

Any suggestions what to do now?

 

unrelated due to the year, on my 04 F-150 the belt tensoner would never stay tight and the ALT could not recharge the battery, two batteries and two altenators, simple, but check your belts...

 

The first thing I did was test the battery and charging system. This is a drain, not a charging issue, the battery is discharging slowly overnight, about .5 volts, it appears to be due to one of the circuits protected by a single fuse as described above.

I'm going to do some more troubleshooting just to make sure the drain is caused by the circuit in question, it appears to be the culprit, but ya never know.