Whirring sound in engine bay 0 C180se

[Davo070]

I have a relatively loud whirring noise (not the blower) in the engine bay of the 07 Challenger, seems to happen when I have stopped running it and continues even after the master battery switch is set to off. Only way I have found to stop it is to disconnect the battery, any ideas what this can be and how I can stop it? Its already cost me 1 battery replaement, before I had really noticed it.

Thanks

 

[RFoster130]

Bilge pump stuck on would be my guess. That will make a noise and it also is connected directly and doesnt go through the battery switch.