Trim button shorting out stereo
 

Hi everyone,

I have just purchased a 2006 Mariah SX18 - the boat has a built in stereo. When I adjust the trim while the stereo is running - the trim seems to be shorting out the stereo speakers. A loud crackling noise comes through the speakers when I am operating the trim switch.

Does anybody know how to fix this? I am wondering if maybe the stereo isn't grounded properly?