I have a 2014 20SL. When I put it in reverse, honk the horn, or turn on the docking lights my stereo and Garmin shut off which are wired into the accessory switch. Voltage seems to be pretty low, barely 12v. The resettle breaker for accessory was a little flaky so I replaced it. No change. Replaced the voltage regulator. No change. Stator test good at .3 ohms. Any ideas?