The water tank typically has four connections. They are just metal protrusions into the tank, and use conductivity of the water to detect level. There is a resistor pack (little orange/red plastic thingies' with wires coming out of it) Four of those wires go to the tank sensors. Bottom one is the common, a white wire. Other three are the level sensors (they read to the common through the water) Top is orange, middle is green, bottom (of the three) is yellow. There are two other wires coming out of the resistor pack, they go to the monitor panel. One is ground, the other is used to light up the appropriate number of LED's on your panel.
BTW: Usually a problem as you described with your kitchen sink is the fault of the faucet assembly itself.
Hope I helped a little.
Rich, MCPO, USN, Ret.
RV Service Tech
RAM pulling 2021 GS TT