Wow your shower goes into the black tank?
On our Axis the bathroom sink goes into the black tank and the shower drains into the grey tank (black is 30 gal, grey is 40 gal).
Originally Posted by Bob Montgomery
the black water tank registers all four lights.
The black tank sensors on all campers are notorious for getting gummed up with stuff from the black tank and end up reading full when it isn't full. You can try to keep the tank clean (frequent flushings when dumping, get a flush kit, etc.) or install new sensors that read better. Many solutions aren't that satisfactory though.