Holding tank indicators all showing full when empty

[Sandfreak]

So going through my new to me 2015 Fuzion 345 and all the tanks are showing full even the empty water tank and batteries..Hard to believe that all the sensors are bad. Can the system be reset?

[dblanch57]

Battery indicator will read full if you are plugged in to 110. Tank indicators are gummed up. You could put water in tanks and a large bag of ice and drive around. Look on youtube for help. Try calgon in the tanks and after a few trips and rinses you might get them to work. Good luck

[ctbruce]

Is both the grey and black tank showing full? And the fresh water tank too? The holding tanks can be filled and some dawn and calgon or Downey added to the tanks and driven around. You may have something clinging on the sensors and it may take a couple of times to dislodge it and get them functional.

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[chuckster57]

If the fresh tank is reading full, I wouldn't use anything other than bleach or an algacide made for potable water systems.

[NorskeBob]

So - - when I traded our 2012 CrossRoads Cruiser (purchased in 2011) - the water tank level indicator did not work - showed empty, the black tank when empty indicates full, the galley sink gray tank when empty would indicate 1/4 and the shower gray tank when empty would indicate empty. I had not tried the "calgon" method to clean the sensors. We just lived with them not being accurate.

The system can not be reset. The water tank connections were good in the monitor panel. I did not want to drop the belly liner to fix the water tank sensors.

[chuckster57]

Part of a PROPER PDI includes filling every tank with fresh water to verify proper operation of sensors and monitor panel. I have opened up many under bellies to correct issues.

Properly maintained, tanks will read correctly for the life of the trailer, IF they are correct at delivery.

[NorskeBob]

Part of a PROPER PDI includes filling every tank with fresh water to verify proper operation of sensors and monitor panel. I have opened up many under bellies to correct issues.

Properly maintained, tanks will read correctly for the life of the trailer, IF they are correct at delivery.

True - I let things slide on our last RV. I had less issues with the level indicators on our previous RVs.

:angel:Interesting that you mention the PDI - the tech did not drain the water in the tanks before we took delivery of the RV. It did help me find that the gray (shower/bath) and black tank handle labels were switched.

[chuckster57]

Since I walk every unit that I PDI, I check that the tanks are drained since our detail department seems to miss that step a lot :facepalm:

[Sandfreak]

Thanks for the tips guys.Found a bad ground at the panel so now battery and fresh water are correct. Both grey and black are still showing full though. Never have had a grey tank do this before.

[Sandfreak]

How much dish soap and fabric softener should a guy ad?Is both the grey and black tank showing full? And the fresh water tank too? The holding tanks can be filled and some dawn and calgon or Downey added to the tanks and driven around. You may have something clinging on the sensors and it may take a couple of times to dislodge it and get them functional.

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[ctbruce]

Try this: http://wheelingit.us/2012/03/21/rv-tank-sensors-the-geo-method/

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[Rick52]

My 2016, 371 had a problem with sensors off when I got it last year. Fortunately I have a sewer system at home. I hooked up the flush hose and really let it run. It took quite awhile to get the tanks completely clean, but my sensors squared up. Both my black tanks where showing 1 and 2 levels when I knew they were pretty much empty....
\

[wildmandan01]

My tanks have been showing anywhere from empty to 1/4 full after emptying. Last weekend, I emptied them and suddenly both grey tanks and the black tank are showing full after emptying! I could buy into the old belief that something may be stuck across the sensors of one of the tanks, but to have all 3 tanks suddenly show full after emptying is a stretch!!
I believe somewhere I lost a ground that all 3 sensors are tied to.

[chuckster57]

If you lose ground they will all read empty.

[Freeheel4life]

Just out of curiosity, what kind of sender is in the tank(s)?? Float on an arm that hinges or a float on a slide that runs up and down??

[Eastham]

ALSO curious how you could put a float in a black tank?

[chuckster57]

Sensors are “probes” that stick out on the side of the tank. They have a conductive tip and when wet allow voltage to pass through.

There are 4 sensors, one being ground. All the sensor wires are connected to a resistor pack. As the level in the tank rises, the probes get wet and the resistance lessens. Full has the least resistance.
Can’t say I’ve ever seen a float in any RV fresh, gray or black tank.

[Eastham]

Good explanation. Seems like it would have a lot of floaters in there with no wires hooked to them.

[BrentB]

Just out of curiosity, what kind of sender is in the tank(s)?? Float on an arm that hinges or a float on a slide that runs up and down??

You can watch the video at this link to see what most tank probes look like. They also have an improved probe that is said to work better:

http://www.rvprobes.com/home.html

[Freeheel4life]

Thanks guys. Normally only dealt with float type senders for fuel and water tanks.
Lots of info here. Great stuff

[mikz86ta]

Bought my 2016 in 2017 used. Took delivery with a missing LED indicator panel. They thought it was bad and ordered a new one. Was 2 months in backorder and I could not wait on that. Took delivery.
Installed the LED board myself. Very simple and I have an extensive electronic background.
The fresh tank level Workd fine as does the battery.
The black and grays were not. The grays sometimes go full empty but one of the two usually hangs up on 1/4. The other 98% of the time goes full empty. The blacks, well the rear with the washer water draining to it will typically got full empty or down to 1/4. The front black I got once to go down to 3/4 but 98% time it reads full.

I myself used drop-ins from day 1. I also have gotten it pretty full and drained it for over an hour. But never helped.
A few weeks ago I did the PowerFlush. Didn't do anything to help. But I then started the Geo Method with some Borax to soften the water and Detergent adding. 1 drain since and not yet helped. I am doing the Geo now, added 2 drop-ins (since I have a whole bag at hand) and then will drain and PowerFlush again in a few days.
Going to try and be presistent. May try adding bleach or whatever the third additive is they do

[djac13]

I have a 2020 cougar and my fresh water and grey tanks show empty even though they have water in both. Has anyone else had this issue?

[travelin texans]

I have a 2020 cougar and my fresh water and grey tanks show empty even though they have water in both. Has anyone else had this issue?

Yes! I'd say that anyone that owns or has owned a RV of any type has had, does have and will have the very same issues. Those sensors are next to totally useless for giving any accurate tank levels.
Learn your rv sounds when the tanks are nearing full & forget about the sensors. The shower will back up when it's full, usually about the time you're all lathered up & the toilet has a very distinctive burp/gurgle when it's nearing full, both are more accurate than the sensors are or ever will be.
Yes you can drain/flush, waste countless bags of ice, spend money on potions & all will work..........til you've filled the tank the next couple times, then it starts over again.

[JRTJH]

Holding tank status indicators typically come with either red or green "led status indicator lights"...

That's a "very good clue" to their true purpose: They, like Christmas decorations, are intended to be used for a couple of weeks annually, need to be "fussed with for hours and hours to get all the lights burning on all the strings of "coiled up mess" and then, shortly after they are all "up and working", it's time to take them down and store them for another year..... Then, the next time you try to use them, the process of "fussing for hours" starts all over again....

Like Christmas lights, if it's worth the hassle to keep them working, the hours of "work" far outweigh the hours of "enjoyment".....

Mine are a "forgotten panel on the wall in the hallway. That panel's only purpose: To house the fresh water pump switch and the water heater gas switch. I can't remember the last time I even looked at the upper half of that panel (where those Christmas lights are located).....

[CampNBrew2]

I love the Christmas light analogy John! True words!

[notanlines]

Obviously we are the exception rather than the rule. We dump when the black tank says 90%, run the black tank rinse every three dumps, use no chemicals, and only use the correct TP. We dump the grey when it reads about 75%, and use the grey tank rinse every three dumps. No chemicals. We put NO solids of any sort through the grey tank. After cooking the pots are scraped relatively clean, no coffee grounds, no cooking grease.
On the other hand, our Salem was 6 years old when we purchased it and the lights have always read zero. No big deal. Danny and others have already said how it's done.

[RickV]

We are on our third 5er in about 10 years and after the first one I pretty much adopted what Danny posted. I tried all the "Internet" fixes with the first one and finally realized I was pretty much trying to Ice Skate Uphill. Now we pretty much use the number of uses for the two grey tanks and know but the sounds when "Blackie" need to be dumped. Trying to get them to work properly is one less thing to waste time messing with.

[Moosemedic]

My tanks have been showing anywhere from empty to 1/4 full after emptying. Last weekend, I emptied them and suddenly both grey tanks and the black tank are showing full after emptying! I could buy into the old belief that something may be stuck across the sensors of one of the tanks, but to have all 3 tanks suddenly show full after emptying is a stretch!!
I believe somewhere I lost a ground that all 3 sensors are tied to.

It’s likely a bad circuit board or a short. No ground breaks the circuit indicating empty as chuckster stated

[dutchmensport]

Glad you found the "ground" and looks like you got a fix. However, the sensors may still need a good cleaning. The absolute easiest way to clean the sensors (unless they are actually broken), is to dump all your tanks (black and grey, flush then if you can), get them as clean as you reasonably can. Then add 5-10 gallons of water, some Dawn dishwashing liquid (generously) and take the camper for a nice drive. The sloshing of the water in the tanks will pulverize against the sensors and scrub them clean. They will work again .... unless they are broken.

Do this every time you travel and your sensors will always work. (unless they are actually broken).

[cw1001!]

Since I walk every unit that I PDI, I check that the tanks are drained since our detail department seems to miss that step a lot :facepalm:

What does PDI mean?

[Canonman]

What does PDI mean?

Pre-Delivery-Inspection Some dealers are better at this than others.
Basically the dealer is supposed to demonstrate that all the operational items in the new RV are in proper working order and show the buyer each items functional use. For example, turn on the furnace and demonstrate that it works as well as how the user operates the furnace. Same for the A/C, power systems, slides, etc..

[travelin texans]

Glad you found the "ground" and looks like you got a fix. However, the sensors may still need a good cleaning. The absolute easiest way to clean the sensors (unless they are actually broken), is to dump all your tanks (black and grey, flush then if you can), get them as clean as you reasonably can. Then add 5-10 gallons of water, some Dawn dishwashing liquid (generously) and take the camper for a nice drive. The sloshing of the water in the tanks will pulverize against the sensors and scrub them clean. They will work again .... unless they are broken.

Do this every time you travel and your sensors will always work. (unless they are actually broken).

I guess every rv I've owned the sensors must have been broke on ALL of them, never had one, no not one, that those sensors were worth the minimal voltage it took to light the little red lights after the 1st couple tank fulls.