Grey tank is empty but the panel shows full

[Cmpdman]

We are out camping with a friend who has an 2016 OutdoorRV travel trailer. model 25RDS.

His grey tank is completely empty (manual inspection at a dum point station), but his panel shows full - all 4 lights are lit up. Any suggestions as to why?

Thanks in advance!

...p.s. Were in a 2016 OutdoorRV Glacier Peak.

[HopsBrewster]

Originally Posted by Cmpdman

We are out camping with a friend who has an 2016 OutdoorRV travel trailer. model 25RDS.

His grey tank is completely empty (manual inspection at a dum point station), but his panel shows full - all 4 lights are lit up. Any suggestions as to why?

Thanks in advance!

...p.s. Were in a 2016 OutdoorRV Glacier Peak.

It could be a bad sensor or a short in the sensor's wire, but very possibly could just be a dirty sensor. It's quite a common problem and there are dozens of threads here on how to clean the tank and sensors.

When that happened to me I put a little vinegar and Dawn detergent in the tank with about 1/2 tank of water then drove it around for 20 minutes. When I drained the tank I could see all kinds of gray gunk through the clear elbow on my drain hose. But the sensors worked again.

[hamm2018]

Originally Posted by Cmpdman

We are out camping with a friend who has an 2016 OutdoorRV travel trailer. model 25RDS.

His grey tank is completely empty (manual inspection at a dum point station), but his panel shows full - all 4 lights are lit up. Any suggestions as to why?

Thanks in advance!

...p.s. Were in a 2016 OutdoorRV Glacier Peak.

It is about normal, they work great until stuff gets on them, then they are done. They will figure out when it needs dumped. Tell them the same will happen with the black tank, sooner or later.
For the black tank when it "burps" it needs to be dumped. For the gray, when you hear it "gurgle" in another gray drain line time to dump.

[Blazing zipp]

Those sensor lights are like politicians. Lites are on but the tank is empty!
Sorry, couldn't help it..

[eddieelk]

For years, they said to put a 20# bag of ice in your tank, and fill it up half way, and drive around. I found out that I could look down the toilet to see the level, and dump the grey tank whenever I had the urge. The panel is useless. Eddie Elk.

[egwilly]

Pretty common, happens to us all the time. I drain and still have lights.

Try filling the tanks 1/3 full after dumping between trips.....the sloshing while towing will clean off the stupid metal sensors that stick out inside the tank. Usually works for us.

Got the be the worst idea ever. The sensors should be outside like some other manufacturers do.

[keymastr]

You don't say which model. My Glacier peak has two gray tanks so you may have only dumped one and still have a full galley tank. My black and first gray tank handles are under the front compartment behind the pin box while the second galley gray tank handle is at the rear drivers side under the skirting.

[rarebear.nm]

Many tank level sensors used at the factories are cheap types that have an electrical probe inside the tank. All it takes is for some "gunk" to form a bridge between a contact and the ground probe and the panel lights up. This is an age old problem with this type of sensor. You can do a cleaning process on a regular basis to try to keep it working, maybe. Some people just judge it by sound or number of days or some other technique.

The better RVs come with some sort of a sonar like sensor strip that attaches to the outside of the tank. Thus nothing to ever gunk it up. These cost more, of course, but they do seem to work better. Sea Level system is an example;

https://www.amazon.com/SeeLevel-709P...1503023&sr=8-2

Link is posted just as a reference point.

[happy2rv]

As others have already said, it's pretty common. The tank monitors used in most RVs are very simple devices that probably cost the RV manufacturers about $3 to make. Their simplicity makes them cheap, but also susceptible to false readings. There are a few things to try, but usually when they start giving false readings, its time to replace the tank probes. People swear by different remedies: Ice in the tank, the GEO method (google it) basically a combination of chemical water softener, bleach, and laundry detergent.

It could be a problem other than the probes. First and foremost, verify the tanks really are empty. The drain could be clogged preventing full drain. From there, you have to decide how much you want to troubleshoot vs having someone else do it. Removing the wiring from the sensor(s) should allow you to verify there isn't a wiring issue. With the wires removed from the sensors, they should show empty.

The sensor probes can be replaced and there are "better" probes available, a lot of people love the Valterra brand probes, https://smile.amazon.com/Valterra-T2...dp/B0136USMXW/. There's a black tank and a gray tank version. I don't have personal experience with them though. Some factory probes are installed similar to the Valterra installation, basically a nut compresses a rubber gasket locking the probe in place. Unfortunately some of the factory probes have to be drilled out as they don't use the nut compression method. You can find videos on Youtube that show how to replace them.

Something like the SeeLevel system is the most reliable long term solution, but for most people its just not worth the cost and hassle of installation.