W203 pre facelift c class keeps making noise while turned off parked up

[Adamzl]

Hi guys i am new to this forum my father has a w203 c class pre facelift a couple months ago the car used to make this noise when parked and turned off a chirping like noise it stopped for a couple months now it has returned and its louder its a electric type of noise not sure how to explain it but it keeps making the noise untill you turn the engine on when disconecting the battery it stops making the noise but then when you connect the battery back and start the engine and turn back off again it starts again i have looked at the fuses but maybe i missed something to do with the alarm system any help would be appreciated cheers

 

[Adamzl]

Btw i have just disconnected the battery im going to leave it disconnected overnight to see if that solves anything

 

[clk320x]

Can you record the noise? Just take a video and upload it to YouTube and put the link here.