Monitor panel lights stay on even when we disconnect sensor

thesuperhappycamper wrote:
When checking levels of the 3 tanks, the monitor panel lights won't turn off even when we disconnect the sensors.

We have cleaned the sensors in the tanks well, but because it is old and hasn't been used, maybe it is rusted??? BUT, wouldn't the lights be off when checked after we have disconnected from the sensors?

Thank you for your help!

Much appreciation,
Michele

The system IF the 3 tank(Fresh/Gray/Black) wires are GROUNDED will display all the LED's. If OPEN, then only the empty light will light. UNLESS you have a defective panel which is unlikely. You need to give more info. Year and Model of the RV. Doug

What does something 30 years ago have to do with today?????? Doug

I visited a storage shed assembly area for PROWLER panels back in the eighties. What I saw made me gag. Six people making the PC board circuits, and soldering discretes and three at the end of the line troubleshooting 50% of the "panels" that couldn't even pass a rudimentary proofing test. Location Pomona, CA. Chew & Spit.

The typical sensor setup uses a resistor block (the plastic/epoxy blob thing that the sensors connect to) and provides a stepped voltage that the monitor display shows as varying lights, stepped because the tank contents short out one or more of the resistors when the level covers the sensor probes.

You apparently either have a malfunctioning display unit (possible but not too likely), a short in the wiring or the resistor pack, or a miscalibrated display unit. Some of the displays have a little adjustment potentiometer to set their sensitivity, and some just have fixed resistors to calibrate them from the factory. If it's the former, tweaking the potentiometer with a little screwdriver (which may require removing the display from its bezel to access the circuit board) might help.

I would tend to suspect a damaged resistor block or a short in the wiring somewhere.