2016 G23 belly ballast sensor access?

[OffTheTop]

Can someone kindly tell me where I can access the Belly Ballast sensor? Did a google search and lots on the Port/Strb but not belly. Thx

[GMLIII]

OffTheTop . Don"t know but if you are not handy or mechanical, I would not attempt the replacement on your own. Even the dealer tells me they are a Mother F to change and I have had 6 replaced on my 2017 G23 by the dealer.

[OffTheTop]

Thanks for the heads up - I like pain and suffering

[OffTheTop]

I have pulled both bow access ports and can only see the intake hose? I removed a backrest and see the vent hose but no sign of a sensor? Pls help

[OffTheTop]

Yay - found it - it’s actually mounted on hose and routed up behind the dash. Is the OEM location? When I unplugged it the voltage shot up and turned red but still did not get and power to fill side of the plug. Should I? I get 12.4v to the drain side of the plug when in drain mode which would seem to make sense as I presume the sensor only affects the fill circuit - am I correct?

[GMLIII]

OffTheTop Sounds like your sensor is toast. Replace it and you will be good to go. This is a very common problem on these boats.

[jpwhit]

I'm not sure I understand what you mean by "fill side and drain side of the plug"? But I'm also not sure it matters for what I'm about to say.

I'm pretty sure the ballast level sender output just connects directly to the PDM so the computer screen can read the information from the level sensor. I know for a fact that the ballast pumps connect to the motor driver outputs on the PDM so the computer screen can control filling and emptying the ballast. Any logic relative to the ballast level sensors and water flow sensors relative to whether the pumps run or not is done in software on the screen.

I don't see how the ballast level sensor could be mounted on a hose. It would have to be on the tank so such that it could measure the water level on the tank. Something mounted on a hose would seem more likely to be sensor to tell the computer if water is flowing or not.

I have a lot more experience with ballast systems on MasterCraft boats, but the computer screens, PDMs, and pumps are the same between both boats. All my Nautique boats are direct drive ski boats. My wake boat and ski boat at the lake house are MasterCraft's. MasterCraft got rid of all these ballast level and water flow sensors long ago and just went to the simpler approach of ballast timers implemented in the computer screen. They let the end user just set the fill and empty times they want for each tank in the settings screen. Simple and reliable approach that also handles the fact that a lot of people upgrade they ballast bag sizes.

[Scooter G]

While you have that opened up it would really nice to have some pictures posted. Like you said there isn't much information out there on the belly ballast.
Thanks, and glad you found it.
https://nautiqueparts.com/ballast-pressure-sensor-v2/
I ran the new style on the rears, working great, use the PN10 Code for 10% off.

[OffTheTop]

Here is a picture of what I am talking about.

There are two vent style hoses that are routed through the forward bulkhead ( separates the belly tank area from the fuel tank compartment. One hose hoes to the over flow vent outlet and the other is routed up to the sensor that is mounted almost the the top of the dash. It is definitely the sensor as it is marked and and when I unplugged it the voltage on the LINC system shot up to over 4V. I guess they put a fitting on the sensor port on the tank with a barb and extended the hose up to this location. I have to believe the water pressure could be strong that high up to trigger the sensor.

I don't know how you would change it otherwise without pulling the fuel tank. I removed all the access ports and you cannot physically see the vent hose or sensor hose as they are against the bulkhead. You can only see the fill/drain port(hose).

I worked in a boat yard in college and know my way around an engine compartment pretty good but this took some head scratching.

[OffTheTop]

BTW you have to remove the STRB backrest in the bow seating area to access. Hope this helps.

[OffTheTop]

I'm not sure I understand what you mean by "fill side and drain side of the plug"? But I'm also not sure it matters for what I'm about to say.
.

Using a voltmeter on one side of the plug (at pump in the bilge) - I get 12.4 volts on one side of the plug when in DRAIN mode. I get no power to either side of the plug in FILL mode.

I assume the pump switched polarity to run backwards but not sure? With just 2 wires going into the pump I don't see how it would work otherwise? Always ready to learn tho

[Scooter G]

The wires of the old style sensors were red, green & black, so it looks like you are quite possibly on the right track. But I'm with jpwhit, I would be almost certain that the sensor would have to be at the tank (bag). Haven't had to take this journey (yet), so we're learning along with you. Someone has been down this road before, haven't had the time to dig around PN to find anything, sounds like you've done a pretty thorough search though.

[jpwhit]

Using a voltmeter on one side of the plug (at pump in the bilge) - I get 12.4 volts on one side of the plug when in DRAIN mode. I get no power to either side of the plug in FILL mode.

I assume the pump switched polarity to run backwards but not sure? With just 2 wires going into the pump I don't see how it would work otherwise? Always ready to learn tho

The pump is connected to an output on the PDM that's an H-Bridge. An H-Bridge is the electronic equivalent to 4 relays that can completely switch the polarity of a dc motor. It's actually more complicated than 4 relays, because it also provides speed and torque control of the motor using Pulse Width Modulation (PWM). Here's a pretty good explanation on wikipedia.

https://en.wikipedia.org/wiki/H-brid...or%20backwards.

[jpwhit]

Using a voltmeter on one side of the plug (at pump in the bilge) - I get 12.4 volts on one side of the plug when in DRAIN mode. I get no power to either side of the plug in FILL mode.

I'm fairly certain you're not getting power in Fill mode because the computer isn't commanding the PDM to turn the pump on due to it not getting the reading it wants to see from the ballast sensor.

On the sensor, that is clearly a pressure sensor, not a level sensor. I had forgotten that at some point Nautique changed from actual fluid level sensors to pressure sensors. So, what I said about it needing to be on the tank instead of the hose doesn't apply to a pressure sensor. I'm not exactly sure how they are using a pressure sensor to determine ballast tank level. Seems like it would be a crude approximation at best due to changes in atmospheric pressure.

[OffTheTop]

Thanks JP - that makes sense. Yes I believe it simply a pressure shut off and fill level is determined by pump run time.