tank lights

They (the black tank)are pretty hard to keep working. Ours usually work for awhile after the RV sits unused, but after a little use it gets pretty inaccurate.

They flat don't work, the readings are unreliable. Just pretend it's like a broken gas guage. In mine it's 2 people heavy use 7 days, lite use 10 days, yours will be differant. Add more people do the math. If teenage girls are involved these calculations go out the window.

The only time I ever did fix one was on a black tank, recipe,
65 lbs ice, big bottle of dawn dish soap, pour into tank drive 100 miles, drain.

Winnebago went standard with non-contact sensors on the outside of the tanks in 2005. The problem is wet gunk building up on the inside tank walls that fools the sensors. If you have black tank flushers make sure you use them each time you dump. Anything you can do to clean the tank walls can help.

As a a full timer my tanks were used 24/7 and I did not have a flusher. I tried all of the fixes and products people recommend and nothing really worked. I even pressure washed the inside of the black tank twice. That worked for a while but then I started getting false readings again.

Friends that were not full timers and used the tanks less seemed to have better luck with cleaners added to the tanks.

I finally just gave up and learned how long to wait before dumping and quit worrying about it.

I have filled my tanks with water and then added a new product called Rid X for motorhomes to the tanks and let them sit for week. I did about a triple dose And it seemed to really help with the sensors. Just an FYI and I got it on the net

Those gauges are notoriously unreliable. It's either condensation or debris on the sensor. Flushing and some home made remedies seem to help. My last MH was the worst, no matter how much I flushed or put cleaner in, the grey almost always read 2/3. In the new MH I installed tank flush on both tanks and I run the flush on every trip. Seems to have helped and they usually read correctly. There are after market sensors and levels you can buy. Depends on how much it bugs you.