We may get commissions for purchases made through links in this post.
Many newer RVs come with a monitor panel, making it easy to keep an eye on what’s happening in your RV. It can let you know how full your holding tanks are, warn you before running out of fresh water, or even show how much propane you have left. It’s convenient to check all these systems with a simple glance – but what happens if your RV monitor panel stops working?
If your RV monitor panel isn’t working correctly, it’s likely one of the following:
- You’ve blown a fuse to the panel.
- The tank sensors need to be cleaned.
- The tank sensors need to be changed.
- There’s a short in the wiring somewhere.
- The readings are off because the panel needs to be calibrated.
- The monitor panel needs to be replaced.
Read further to learn more. First, we’ll cover what, exactly, the monitor panel is and how it works. Then we’ll explain some of the common problems with the panel, like bad wiring or a blown a fuse. Next, we’ll explain how the tank sensors work – and how to know if they need to be cleaned or replaced. Finally, we’ll explain the best way to calibrate the panel for accurate tank readings.
How Do RV Monitor Panels Work?
Most RV monitor panels give the status of the battery and the freshwater, greywater, and black water tanks. Your RV might use another tank in addition, such as propane, that is also included on the panel.
They use a series of lights to tell you if each tank is full, partially full, or empty. LED lights also indicate if the battery is full, half-charged, or dead.
Panels can vary a little, depending on the manufacturer. Some let you read the status of all the tanks and the battery at the same time.
Others require you to select between each option for the reading – for example, you have to push a button to read the blackwater tank, then another button to read the fresh water tank, etc.
The levels they read may also vary – but standard gauges like empty, 1/3, 2/3, and full are common. Some panels have extra buttons to turn on fixtures like an electric water heater, gas water heater, or water pump.
How Do You Read An RV Monitor Panel?
Most work through a series of small LED lights. One light is the lowest reading (“empty” in most cases), while four lights are the highest (or “full”). For example, a half-full black water tank will trip the “empty” and the “1/3 full” sensor, kicking those lights on. It isn’t high enough to trip the “2/3” sensor, so the higher lights remain off for the time being.
Since displays vary from camper to camper, the best way to know the specifics for your panel is to consult the user manual.
How To Deal With A Blown Fuse
There’s a pretty simple way to tell if you’ve blown a fuse. Does the monitor have power? If it’s doing nothing, not even turning on, it’s usually as simple as changing the fuse.
It’s a good idea to always keep a few spare fuses in your RV, just in case. Changing them is easy, as you can see in this video:
How Do RV Tank Level Sensors Work?
RV tank level sensors read the tank levels through 4 pins placed in each tank in the appropriate place. Wires connect to the panel, sending the reading back to the panel. The pins should, more or less, be in the correct spot to read empty, full, and everything in between.
It’s important to keep in mind, though, that the pins are placed more like a “rough estimate” than a precise measurement. You may find that one of your tanks seems to stay on 1/3 full longer than it should, for example, because there’s a bit of extra gap between the sensors. They aren’t always placed perfectly equal and offer an approximation.
My Tank Sensors Read The Wrong Level – How Do I Clean The Sensor?
If one of your tanks seems to be stuck, it may just need to be cleaned. For example, your tank may read as full even when you know it was just emptied. This usually means something is covering the corresponding sensor, tricking it into believing the tank is still full.
Flush the tank out by filling it half-full of liquid and adding cleaner. Drive the RV around with frequent stops and starts, letting the motion of the water clean the tank out.
My Tank Read Never Changes – How To Change A Bad Sensor?
If your tank readings are wrong, start by trying to clean the tank as described above. If that doesn’t work, you may have a bad sensor. Because of all the dirty stuff the sensors are exposed to every day, it’s a common problem. This video can help you change the sensor:
The Wiring To The Panel Has A Short
One faulty sensor affects just one reading. On the other hand, if all your tanks give the same (incorrect) reading all the time, it’s probably a short in your wiring or monitor panel.
For example, if all three holding tanks always say empty, even when you know that’s incorrect, that shows that the correct information isn’t getting to the panel. Unless you’re good with electrical issues, you should probably leave this one to a trained RV tech.
How Do You Calibrate RV Tank Monitors?
If your tanks give consistent readings, but they seem only “sort of” accurate, you might need to calibrate for more exact readings. The only tool you need to calibrate your RV tank monitor panel is a Phillips head screwdriver. Above each tank is a small hole with a screw inside. This screw is how you make adjustments to calibrate the corresponding tank.
There’s no way to calibrate the battery reading. And remember, each monitor panel may be different. This guide applies to most RVs but always check your user manual.
Calibrating the Freshwater Tank/Propane Tank
Calibrating the freshwater tank is easy – first, fill it until it begins to overflow.
Now that you know the tank truly is full use your screwdriver to turn the adjustment screw. This is the screw just above the freshwater button.
Turn it to the left until it goes down a level, like 2/3 full. Then turn it back to the right till the light reads full once again. Do not over-adjust – you want to stop as soon as the full light comes on so that it reads accurately.
If you have any other tanks, like propane, that you can easily tell are full, you can calibrate them the same way. Just wait till you have a new, full tank. Then adjust the screw to the left until it goes down a level. Move the screw right until it reads full again, and stop before you over-adjust.
Calibrating the Greywater/Blackwater Tanks
The greywater and blackwater tanks are similar to the freshwater. Just keep in mind that you want the full light to come on before the tank is full, unlike the freshwater. Otherwise, it doesn’t give you any warning to dump the tank.
Fill each tank by running water in the sink for the grey water or down the toilet for black. When the full light comes on, stop.
At this point, you need to know how much extra space the tank still has. This lets you know if the light is coming on at the right time. Conversely, it also enables you to know if the light needs adjusting as it’s too early or late.
RV Geeks suggest using a one-gallon pitcher to continue adding water. Count each gallon until the water backs up. At this point, you can accurately tell precisely how many gallons of space were available in the tank when the light came on.
Remember – you need to know how much space you have for a cushion. If you can only add a gallon or two before overflow, or if you can add 20 gallons, it needs calibrating. Turn the adjustment screw slightly to the right if it’s reading full too soon (when the tank is nowhere near full). Turn the screw slightly left if you want the “full” reading to come a bit earlier.
It doesn’t take much, so go easy. A tiny quarter-turn of the screw makes a significant change. It may take some trial and error to get the tanks reading where you want, so definitely do this in a place with hookups, where it’s easy to dump later.
Replacing The Monitor Panel
If the panel turns on, but nothing works, you might have to change the panel. They can go bad, making all the readings incorrect. One error indicates a problem with the source of information, but lots of issues indicate the problem is the panel itself.
Remember, the panel should give you information on several unrelated systems – like the battery and the holding tanks. It’s rare for all of those systems to go bad simultaneously, though it’s common for the panel to go bad. Some people also replace the panel to get a better, more accurate one.
If your RV monitor panel isn’t working and won’t turn on, it’s probably a blown fuse. When tank readings are inaccurate, clean or replace the tank sensors. Consider bad wiring or a broken panel if all the readings are wrong. If you get readings, but they aren’t very exact, try calibrating for better results.