Strange buzzing

[DanBOtt]

I just picked up my 97 318i convertible from storage, and it is making a strange slight buzzing sound from the center of the dash. Doesn't matter if the ignition is on or off, or whether the key is in. The radio is requesting a code, and the antitheft LED is blinking normally.
Any idea what is making this buzzing sound?
Thanks

[E36328Coupe]

Dual zone climate / AC ? Little fan sucks air in to read temp. Should stop 30secs to a few mins after ignition off

[woody328is]

Did you have to jump start it to drive? A very weak or near dead battery can cause electronics to do crazy things.

[66 6]

I agree with both Coupe and Woody. Both potential sources of the issue.

[DanBOtt]

Ah, that makes sense. It stops after a while.
Thanks