[Evo_3_]

Hey guys, got a problem with the evo 3
i got dropped off at work in it in the morning and the car was fine. Brother drove it home.
When i got back home later in the evening, the car was parked outside making a whirring sound under the bonnet
right behind the passenger headlight somewhere, i popped the bonnet and had a listen

It sounds like a normal small motor whirring away, even though the car is turned off, i thought it might be the intercooler water spray motor but thats not it.

It has now killed my battery so the sound has stopped.

I have no idea what this could be, checked all fluids and they all fine, not sure what other parts are behind the passenger front wing in the engine bay so dont know what it is.

Any ideas?

Any help will be appreciated guys.
Thanks