2002 SN 196 - Low Dash voltage, Upgrade/rewire?

[windsurfnut]

Our 2002 SN 196 has started to show low voltage. The heater will really drop the voltage on the dash and the alternator will start to whine. Is there a recommended upgrade to dash wiring? Use a relay?

[windsurfnut]

Battery is good and new.

[SilentSeven]

EDIT: Re-read your post. The alternator whining could be a loose belt and even a failing alternator. Start by checking your belt tension, try the ground cleaning (it's easy) and if that doesn't work - have your alternator bench tested to see if it's working correctly.

<first post>

The prior model Ski Nautique had well known dash and power issues that I'm pretty sure are resolved in your model. The fix for that model was to run secondary power and grounding that addressed problems when you attached additional devices - like an upgraded stereo headunit or perfect pass. I did this fix in my 97 ski and worked great. I don't think any of this applies to your model.

Your model should have a PME distribution box like this - correct?

https://nautiqueparts.com/breaker-bo...ct-year-model/

Before you do anything, make sure your alternator belt is not slipping. Also, what voltages are you seeing when the boat is running with accessories on? On my 2004 model, I'll see voltage drops when the engine is off and I flip on accessories but the voltage stays stable when the engine is running. I have replaced the in-dash power plug with one of these phone charger models that have a voltage meter - it's cool as it's easy way to monitor system voltage when the engine is both off and on.

https://www.amazon.com/Charger-Socke.../dp/B08TMDTQQV

I suspect the most likely issue with your boat is poor grounding. I'd start by cleaning the battery posts, cables and making sure the secondary power/ground wires off the cables are also clean. Also consider removing and cleaning the main engine block ground wire where it attaches to the engine. Start here and if that makes a different.