What's draining my battery?

[BigT's93]

After 1 Week at teh beach, I come back and my battery was almost dead, it wouldn't turn the engine over. I don't have any aftermarket "stuff" and the radio alarm is the only thing blinking. The Battery is 6 months old and tested "good". Any Idea what may be pulling juice?
1993 740 IL.

[witeshark]

You sure there's no interior or trunk light stuck on?

[BigT's93]

Yep, no light on anywhere. I actually turned the switch off so no light comes on at all when I open a door. Only the trunk light comes on and I'm pretty sure it goes off when the trunk is closed. I peeped through the backseat armrest and could not see any light. I am not too worried about it, but it is puzzling.

[slidebabyslide]

my 740iL does the same thing.

any suggestions?

[darkhorse737]

when u shut-off ignition... listen for any abnormal sounds ticking, knocking humming...

Try the same thing with doors ajar, and yet again;
with doors locked.

in a darkrooms try the same thing and observe any lights that may be still on.

I have had bimmer cases where the injectors were clicking away the whole night. Ignition OFF, KEY OUT, doors locked.

a faulty fuel relay circuit was the culprit... took me MONTHS! to figure out why ;-)

[BigT's93]

^^ Thanks for the info and I'll try your suggestions. When I turn off the ignition I sometimes hear a rhythmic buzz. The "buzz" lasts for maybe a 1/2 second and repeats every 3 seconds or so, then stops. WTF? The longest my 740 IL would sit without being cranked is maybe a weekend. It took a 10 day vacation for the battery to drain to the point it would not turn over the engine. If I never find the "gremlin" causing this it may not be an issue. It is puzzling though. Thanks again!!!