Holding tank sensors


bigal595

New Member
Purchased a used B+ and all the tanks (black, gray and fresh) show half full all the time whether they are full or empty is there anything that can be done, and maybe what is the problem here,could it be electrical? Not a real big problem but would at least like to know how full the fresh tank is.
 

Grandview Trailer Sa

Senior Member
Holding tank sensors

Sounds like an electrical problem to me. The lights on the monitor panel are activated by what I call a "contolled short". Simply put, the sensors are wired together and there is a ground and 3 positive probes. When water or substance gets on the first probe, it shorts to ground and the first light comes on. As the water level rises, the same thing happens with each probe and it is shown on the monitor panel lights.

If you are getting the same reading on every tank, full or empty, I would suspect the monitor panel has gone bad or has a bad ground. It would be a good idea to check the grounds at each tank, but I really doubt that could be it.
 

afhauler

New Member
Holding tank sensors

A trick that was given to us years ago was to put in a couple of tablespoons of baking soda when filling the fresh water. It doesn't affect the taste but it goes through the system and seems to clean the contacts for the tank misers. It always worked pretty good for us.
 

foutsdw

New Member
Holding tank sensors

quote:Originally posted by bigal595

Purchased a used B+ and all the tanks (black, gray and fresh) show half full all the time whether they are full or empty is there anything that can be done, and maybe what is the problem here,could it be electrical? Not a real big problem but would at least like to know how full the fresh tank is.
 

foutsdw

New Member
Holding tank sensors

I just bought a used Class A with the same problem. I took it to a RV service place and ended up putting new sensors, wires and panel. Just left the old ones in place.

Dave
Oceanside, CA
 

K9 Guy

New Member
Holding tank sensors

Last weekend, I removed the Fresh Water holding tanks to get to a leaking fitting. While they (2) were out, I rinsed them with a bleach solution. Not only did it get the 13 years of build-up out of them, but now the sensors work. It could have been that the sensors had a film on them.
Now the water taste better and is clearer, too!
 

ARCHER

Senior Member
Re: Holding tank sensors

taste better and cheaper too from "holding tanks". You lost me but I really don't need an answer.... :dead:
 

Kirk

Senior Member
Re: Holding tank sensors

Nearly all of the level sensor systems in RVs have an adjustment for the level detection that is located behind the face plate of the display. It is very common for that to need adjustment and the fact that both say the same is an indication that they probably have that need. If you remove the fact plate, look very near the indicator for each tank. The adjustment is usually a very small potentiometer that must be adjusted with a jeweler's screwdriver. Usually the clockwise direction increases the level indication, but all you need to do is to turn it one way until it changes. If the change was in the proper direction, just continue until the empty is just indicated. If the level goes up, turn the other way until the empty just starts to show. It is a very easy but little known adjustment. A Master Certified RV Tech. taught me that little trick and I have solved the problem of levels in many RVs with it.
 

tallyo

New Member
Re: Holding tank sensors

We had a similar problem and here's the sad story.

The converter was bad. But to find that out, they replaced all sensors, rewired to control panel and put in a new control panel. The concern I have is that once the liquid has passed by a sensor the next sensor picks up the reading so I don't think a completely accurate reading is possible.

The good news for me all this labor time and parts were under a factory warranty.
 
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