Hey everyone... I tried posting this in the Car Audio area, but got no responses - I hope to have better luck in this area.

I have an '03 CLK 500 with the MB bluetooth kit installed. Whenever I'm on the phone with people, there's a lot of loud background noise, as if my windows are down, even though they're not. Why is this and is there anything I can do to fix it? Thanks in advance for your help!