Engine and Wakeplate Noise Feedback thru speakers
	
	
		My 09 XLV Gravity is getting feedback noise thru the speakers when the engine is running even with the stereo OFF.  I also get feedback noise from my wakeplate motor when I'm adjusting it.  Same thing...  doesn't matter if the stereo is OFF or ON.  When I turn the Stereo switch On and OFF is stops if for a few seconds but the noise comes back.  I know this is a grounding problem but not sure where to start troubleshooting.  If anyone's had this problem before, please let me know the quick solution.