monitor panel black tank display

There are replacements for the "red thing" if you buy the full KIB repair kit which includes a new monitor plus the wiring. The wiring from each of the probes goes to the "red thing" which doesn't do anything electrical I think other than convey the grounds back to the monitor. I am guessing but think perhaps that the four probe wires are just grounds which complete the circuit which causes the idiot lights to light and the 12VDC is supplied to the panel from elsewhere. The wires run along a long loom from front to rear of my 5ver and enter somewhere in the back with the wires going to the electrical box. The wiring is what it is as it is pretty much hard (if not impossible) to trace. One symptom is that ALL FOUR idiot lights are lit so that would mean the false ground is not where the wires come out of the probes otherwise only one would light an idiot light if only one were damaged. It is possible that the "red thing" is buggered as I have no idea its function but not sure how it could produce a false ground signal even if all the wires from the probes were touching inside. A replacement monitor which is plug and play is $27 and I am leaning that way as the wiring is just too darn hard to chase.