Black water sensors don't work- where to start?

Stikman · 04-12-2017, 05:32 PM

Went camping last weekend in our 2016 Palomino 318 tsbhk. Kept a close eye on tank levels just because ( first time in this camper). Noticed the black tank level never went above "E" . After 5 days, I looked down in the toilet and the level looked to be about where the pipe from the toilet enters the tank. I went ahead and emptied it and did a tank flush. After I emptied it, I looked again and couldn't see the bottom of the tank. It looks like there is some type of baffle there. Just wondering where to start looking to run this down as I don't think the sensors are working at all. I would rather ask someone with more experience to maybe save some time diagnosing this. Thanks.

gkehman · 04-12-2017, 05:52 PM

I am experiencing the same problem with a new 2016 Rockwood 2304KS. I filled the tank to the bottom of the toilet 3 times and never got a reading except empty. All other monitors on the panel appear to be working properly so I think it has something to do with the sensors but have no idea where to start troubleshooting.

zuterbru · 04-12-2017, 05:56 PM

Black tank sensors never work reliably. Turn off the water supply, open up the toilet grab a flashlight and take a look, only reliable way to tell.

donniedu · 04-12-2017, 05:56 PM

LOL, tank sensors are notoriously inaccurate. How did we ever RV in the old days before mfgs started putting them on our RVs? There are tons of home remidies, and probably the best one is 10 pounds of curshed ice, half a cup of Calgon and half a cup of dawn dish soap followed by about 10 gallons of water. Hook up and drive around for about 30 minutes. And dump.

gkehman · 04-12-2017, 06:04 PM

I would think they would work the first time, before they had time to get fouled. It is not like it is a "false" reading. It is not reading at all.

Stikman · 04-12-2017, 07:07 PM

Yeah , I don't think it's a contamination problem. I thinks it's more of a wiring issue.

fonzie · 04-12-2017, 07:16 PM

There is older threads that give info....

https://www.google.ca/search?q=black...I4nljwTv-ILgBA

RitaB · 04-13-2017, 12:26 PM

I had a similar problem with my new 2016 Surveyor that we picked up late last year. Only got out once, but that was enough. The black tank always showed empty. The last day there I also checked the gray tank and for the heck of it the fresh water. The grey looked as I expected, but the fresh water showed 3/4. It was empty. Leads me to believe the wires are switched. We didn't get to go out after that, so I didn't get to check out my idea. We'll be going out for the first time soon so I'll check this out.

jnjwright82 · 04-13-2017, 12:37 PM

We had exterior sensors by Garnett See Level installed couple months ago on all tanks. They were able to locate wiring from old sensors to our panel area and used that to install their panel. We actually have correct readings now.

Stikman · 04-13-2017, 01:04 PM

Fonzie, thanks for the link. I think I may have a different system, but I'm going to take a look this weekend if I get a chance. I may also fill the gray and fresh water tank while I'm at it to check them also.

Oaklevel · 04-13-2017, 01:10 PM

Many of us old timers don't bother with using them. Over the years we know how long a tank usually takes to fill.

JerryR · 04-13-2017, 09:38 PM

On my third RV with tank sensors now. First one did not have them. None of the 3 sets of waste tank sensors were ever reliable. The fresh water ones always seem to work okay. The black tank sensors always, after the first use in the season, indicate full, rather than empty like yours do.

So... I go by two things: Time since last black water dump (maximum about 6 days with two people on board) and whether the toilet sorta bubbles when dumping a full tank, which I take as an indication that the tank is full enough to restrict the vent.

Jerry
2011 Cardinal Fiver
2012 Ford F250 4WD Diesel

Stikman · 04-17-2017, 12:10 PM

Well, I filled the gray tank this weekend and it still reads empty. I pulled the control panel out looking for any wires pulled loose. No luck . If the weather holds out this week I'm going to try and pull some of the panels down and check the wiring to the sensors. I'll let you know what I find.

gkehman · 04-17-2017, 12:16 PM

Thanks for the update. I checked my other tanks and they are all working properly. The only problem I still have is the black water tank ready empty at all times. I think I will need to pull the underbody and take a look myself. There is either a wiring problem or a bad sensor. May upgrade the sensors if that proves to be the problem. Won't be able to get to mine for a while.

Stikman · 04-18-2017, 12:59 PM

I pulled the panel yesterday on the gray and black tank. The gray tank had a loose ground wire ( the white one ) and the black tank ground wire wasn't even connected. I think the nut was loose and vibrated off. Hooked it back up and all works now! Thanks to all for their help!

gkehman · 05-02-2017, 08:10 AM

I finally got the trailer out for the weekend and did a little diagnostic work on the black water system. I removed the control panel and switched the black water and fresh water wires. Now my black water sensors worked but the fresh water did not. The circuit board must be defective. A warranty claim has been submitted to Forest River through my dealer. Hope it arrives soon so I can get this fixed. Thanks for all your help.

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