Black and Gray sensors not working

[mlmaschmeyer]

My 26' Wildwood is a 2017. I used it by myself only a few times before the warranty expired so I never thought about checking the tanks to see how full they were. Go ahead 3 years I had family members stay with me a couple nights and I kept pressing the buttons to be sure the gray and black tanks were not getting too full. The last day water came up in the bathtub. The gray still only showed one green light for 1/4 full. The same for the black tank. I honestly don't think they ever worked. I checked the connections for tightness on the sensors on each tank. I also removed the panel holding the sensor buttons to check for any loose connections. I also put a cleaning solution which was recommended to use in the tanks to clean the sensors. Filled each one half way and drove around a large field zigging, zagging and making abrupt stops to swish the stuff around in the tanks. Drained and refilled each one twice and still only 1 green light for gray and black. Any ideas? Thank you.

[Reverse_snowbird]

These sensors are known for their unreliability. They do make sensors that can be retrofitted, but we've never tried them. You may have to clean the tanks more than once, but there's no guarantee. Most of us have just learned to live with the unreliability.

[bikendan]

Originally Posted by mlmaschmeyer

I also put a cleaning solution which was recommended to use in the tanks to clean the sensors. Filled each one half way and drove around a large field zigging, zagging and making abrupt stops to swish the stuff around in the tanks. Drained and refilled each one twice and still only 1 green light for gray and black. Any ideas? Thank you.

Adding a cleaning solution to tanks that have sat for 3 years and driving around for a while, probably not going to do much.
If you don't have a black tank flush, I would buy a tank flush wand and see if it can clear the black tank sensor.