In my Benimar Perseo 590, the waste water tank level readout is faulty and almost always shows about 14 or 16 litres spare capacity no matter how much water is in the tank. But once, just for a while it showed a sensible reading.

It would appear that it could be a faulty sensor or loose connection.

Does anyone know what the tank level sensor looks like and where it is located? Does anyone know it if is accessible from inside the 'van?