Buzzing/Fan noise

[J0N35Y]

Bear with me everyone. Just noticed that with the ignition on I get a sort of buzzing whirring noise from the heater control panel. Seems to quieten down if I put my hand over the grill in the middle of the panel. Anybody have any ideas?? It has dual climate. TIA

 

[Jeffseye]

I had my radio out today fitting a iPod lead when i put it back in a noticed a buzzing ask a friend he says there is a small fan inside it behind the small grill probably full of dust etc I blew into the grill a few times and it seemed to be quiet now