Does anyone know how the tank level data is sent back to the control panel? I see that there is a power and ground plus one wire for each sensor. I assume that there is a common ground but I dont know how each sensor sends information over the positive. I am thinking when I push the button on the control panel it runs power through the sensor and measures the resistance. Just playing around with some upgrade stuff. Thinking about touch screens and what not.
Most of the cheap OEM level monitors are one wire to each level sensor. The "sensors" are simple open electrical terminals. The water touching the terminal grounds the wire allowing current to flow and light the simple LED light for that level. The tank has a ground near the bottom. The LED light is grounded through the push button on the panel.