Trouble shoot Fresh Water Tank Monitor

[Alanj]

Hello, I have a 2021 2600RB and I am trying to isolate a problem. The fresh water tank level indicator no longer works. It shows 1/3 full when the tank is full. The grey tank monitoring works well. I found the x180t and see the input wires for tank monitoring. I understand the tank level monitors have resistors, so I am guessing that when the tank is empty all switches are open and there is no current. I am guessing that as the water rises the wire into the x180T reports increasing voltage in steps. Is this correct? Is there there a separate module somewhere that runs the tank level monitors? I am looking to consult a bit. I am hoping to use my multi-meter to determine if I need to replace an electronic component or drop the under-trailer fabric and search for a loose connection at the two highest sensors. I appreciate your willingness to help.

[howson]

Alanj

You wrote, I am guessing that as the water rises the wire into the x180T reports increasing voltage in steps. Is this correct? I believe your theory of operation is correct. As the different sensors in the tank are triggered the voltage input to the X180T changes. The X180T then triggers the lights on the control panel via a command sent through the CANBUS. (The Imagine's panel is 100% controlled via the CANBUS connection from the X180T--there are no manual inputs to the panel.)



Note how the wires connected to the x180T are shown as inputs. I assume (hate that word!) this means from the sensing harness.



So my educated guess is that 12vDC is supplied to the tank harness and sensors at or near the tank. The combined output voltage of the sensors that are active (due to water level) is sent to the X180T via one wire (in this case the one we're interested in is the White Fresh Tank wire).

MyRVWorks (YouTube channel) has an interesting video on the RV tank harness topic and how the sensors work. Not 100% applicable since you have the CompassConnect system, but good enough to get a basic understanding. Pay special attention to how a multimeter can fail to measure the ohms value of the sensors correctly (Darren goes into depth on the topic). https://www.youtube.com/watch?v=v9yAIC4M36U

Darren also linked to a KIB owner's manual. Again, not 100% applicable since that's not the system in our RV but it has a lot of information: https://www.dutchmen.com/resources/m...nformation.pdf

Bottom line: based on what I've reviewed this morning, I'd be looking for a harness wiring issue at or near the tank.

Good luck -- and please report back what you find. Pics would be great, too!

[Alanj]

howson

Thank you for this thorough reply. I will digest it and let you know how things go.