Grey 2 tank "full" all the time

Common problem - you can fix it but it will probably go bad again.

Usually takes a good cleaning on the inside of the tank

The tank sensors aren't very reliable. Crud gets stuck on them and the readings are off. You'll learn after a few trips how long you can stay out before the tank is really full.

Never use the built in sensors on any of our tanks. We ignore them. Best practice is to get a "feel" for how much each tank holds. That comes with just a bit of experience.

If you are at a full hook up site for a few days, experiment by not dumping until the bathtub begins to not drain. You've reached your limit. Then you'll know how much you can run before you have to dump.

Sensors very seldom work after you pull out of the dealership the first time!

Some will say black electrical tape.... Place it over the sensor gauge lights and enjoy ! Don't go by them....Joe

porkchop1221 wrote:
Just recently came back from a long trip and noticed on our last leg of the trip that our grey tank is showing full. We know it's empty. we haven't been using the sink at all!

I'm thinking it's a loose wire maybe but I'm not sure.

Does anyone have any tips on how to diagnose the problem?

Thanks

Do you have more than one grey tank that you are not emptying ???? Our TH has 2 grey & one Black tank.....just a thought

One of the best mods I've done to my toyhauler.

My Rvision had 2 grey tanks and the dump for the second one was behind the axles tucked up behind the frame. Difficult to see. You might check and see if you have a seperate dump for the 2nd tank.

It was a long time before I found it. Not until the kitchen sink backed up then I started chasing the drain and found it.

We have two grey tanks and I know it's behind the second slide... I think the first lever (closest to the TV) is the black tank. The second one is grey 1 for our shower/bathroom, and the one behind the slide is the grey 2 is for the kitchen. Thing is we HARDLY ever use that tank. I make DH throw things out in the toilet (if there is food etc) and we wash our dishes elsewhere.... Black tank is also always 1/3 full and we have a black tank flush built into the system. Everything comes out clear after a few flushs and I try to leave water at the bottom.

The RV is a little over a year old.

I will try the black tape route, but if there is a short fix that I can try, I'd like to try ;)

Thanks!

Sensors do get "stuff" stuck on them and as a result give false readings.
While I do not necessarily disagree with general reliability of OE sensors, the sensors worked for complete time of ownership in our last two haulers.
Going to keep my fingers crossed 3rd time is a charm with new unit as well….

That said – one trick I always used after recommended by a season RV’er: Either when sensors gave false reading for extended period of time or periodically if no sensor issues encountered after several trips was to dump 2-3 bags of ice and 2 cups bleach into black tank right before you get on the road for at least a 1 – 2 hour pull.

Yes, crappy sensor design.. done for minimal cost I would suspect..
at least yours are connected to the correct tank. My grey and black are swapped..! I filled my grey to clean/rinse it and while filling i noticed the black tank gauge was climbing !! I know the black is empty as I just gave it a real good clean and the valve is open..

Thanks all. I will try the tricks!