What does this part do?
 

Have a 2007 R350.

Water keeps getting into car through vents.

Finally caused the HK amp to stop working.

I took the seat out..saw a bunch of moisture around the HK amp... amp looks ok...

The part under the HK amp labeled "peiker" a2518201389 however looks damp and fried.

What does it do?

Thanks for any help......