2003 Sebring; 2.7 engine; automatic....I hear a strange 'pop' under the dashboard, behind the instrument cluster sometimes when I hit the brakes. Only happens in stop and go traffic when I press the pedal there is a popping or snapping sound under the dashboard. Not every time and usually when I hit the brakes gently/slowly. Brake fluid is at normal level and the brakes seem to work just fine. What could be causing this sound? Thanks.