SeeLevel II Tank Monitoring System

A frequent post on Facebook or IRV2 by many RVers concerns the tank monitoring systems in their coaches.  Usually, the factory-installed system shows you the levels of your tanks in 1/3 increments.  For example, you'll only know that your gray tank is 2/3 full - and that's the last thing you'll see before it backs up into your shower.

The people at Garnet Instruments Ltd provide a solution for this with their SeeLevel II Tank Monitor.  Using the SLII, you can read your fluid levels in increments of 5% or less - much better than the default using thirds.

Garnet offers a good variety of monitoring systems, including some that continually show levels and several that show propane levels.

When you install the SLII, you can usually use the existing wiring already in your coach to replace your old monitoring system with the new one; there are no additional wires to run.  Each of your three tanks (fresh, gray and black) has sensors installed with two wires that run back to the monitor inside of your coach.  Twelve volt power is usually supplied to the monitor, which in turn "feeds" the power to the sensors.  When connecting the SLII, you use those same wires that run from the sensors on the tanks back up to the monitor.

Having read a lot about this system over the past few years and seeing many recommendations for it, I knew that I had to have one.  One of the things I really wanted was to not only replace my existing monitor, but to add another one in the wet bay.  The SeeLevel system easily supports this, and in many cases you still don't have to add additional wiring.

Norm MacLeod - Expert SeeLevel Installer

I got really lucky when my good friend Norm MacLeod (NKK & Hoots member extraordinaire and, with his wife Ellen, author of the great Norm & Ellen's Miss Adventure blog), told me that he had installed the SLII in his coach and would be happy to help me install mine.  Knowing that Norm is great with details and is quite the handyman, I eagerly accepted the offer and we set up a time to do it shortly before the 2017 Tampa RV Show.

The morning we were going to do the install, Norm rolls up to our site in his golf cart looking like the Home Depot tool department on wheels.  He had chosen all of the tools needed for the job, brought quite a collection of wire connectors, and had even made a bezel for the new inside monitor because it was smaller than the old one and he wanted it to be perfect - which it was.  When he laid everything out on the table he brought over, I noticed a styrofoam lid (one of those you use for takeout food) that had a bunch of screws with their tips screwed into it.  The screws had all been spray painted black.  At first, I thought it was some sort of "device" he had made to string wire or something.  Nope.  Norm had painted the heads of the screws so that they would match the monitor plates!

Needless to say, Norm had already (when he installed the SLII on his own coach) gone through most of the research and wiring diagrams to the point where my installation would go much smoother. And it did.  For the next six hours, I became the occasional operating room nurse - handing Norm a few tools and fetching pencils - while he whipped around from one bay to the next pulling wire and completing the installation.  Whenever he pulled out a connector with multiple wires, or simply pulled a single wire from behind a panel, he took the time to prepare a wire label with his label maker and ensure that nothing would get messed up.  We didn't want to "get our wires crossed".

At the very end, Norm attached the two displays - one in the wet bay and the other in the coach - and we took readings...and it worked the first time.

Many thanks to Norm for all of the work he did!  Such a nice thing to do.

Installation Steps for the SeeLevel II

My coach is a 2015 Newmar Dutch Star 4369, so the things I mention here particularly apply to that rig.  However, my understanding is that the installation procedure is the same for just about all coaches.  The only difference is where things are located.

My rig is all-electric, so I didn't need to monitor propane.  I wanted two displays instead of one because I wanted to add one to the wet bay.  And I wanted to monitor three tanks:  fresh, gray and black.   Accordingly, I ordered two of the Model 709-P3 display units.  These show levels for the battery and the three tanks at the press of a button.  One press of a button displays the level in percent for about five seconds.  Two presses of a button keeps the percent display up for about five minutes so that you can monitor it as it changes.

Part of the order is for the sensor strips that attach to the sides of the tanks.  These strips kind of work like sonar in that they look "through" the tank and can see where there's liquid vs. air.  The strips are mounted vertically on the tanks and have two wires coming out of the top of them that will be connected to the remote monitors.

The display panel also includes a button that allows you to turn on your water pump.  The button that does this is a rocker switch (up is on, down is off).  However, my coach's water pump requires a momentary switch.  That is, you just apply power for a second and the pump "toggles" either on or off.  I had to order these momentary switches to replace the ones that Garnet installs on the SLII display board. I bought the ones Norm recommended:  JR Products 12815 Black SPST Mini Mom-On/Off Switch.

Here's a photo of everything that was installed.  All but the two switches were ordered from Garnet (or anyplace else that sells them).  The switches were ordered from the link above.

Switches (topLeft) Displays (bottomLeft), Sensors, Monitor screws, and Manual

In my coach, the tanks are between the pegboard bay and the wet bay.  The wiring for the existing sensors runs right behind the wet bay.  This made it easier to tap into the existing sensor wiring that ran from the tanks to the display in the coach, and still add a monitor in the wet bay.

There are quite a few videos on YouTube that go over SeeLevel II installation, so I'm not going to get bogged down in the details.  But it may be helpful to let you know the steps you'll have to take to do the sort of install that Norm did on my Dutch Star:

1.  Remove the pegboard from the passenger side bay.  It is in front of the tanks.

2.  Find the blue & gray wires in the wiring harness to your right as you face the pegboard bay.  All of the sensors will tap into these two wires.

3.  In the wet bay, drill out a hole to put in the new display.  Be sure to measure the display accurately so that the hole won't be so big that you can't put the screws in to hold it.  We chose to dremel out the area surrounding the existing water pump switch, since the new display will have a new switch that will replace it.

4.  Pull the wires off the back of the existing water pump switch (label everything before you pull any wire off of any device OR cut any wire!!). 

5.  Find the tank sensor wires behind the wet bay panel and pull them through the hole. 

6.  Go inside to the existing indoor display in the cabinet above the passenger.  Remove the display and label all wires coming into the connector.

7.  Replace the water pump rocker switches on the new monitors with the new momentary switches.  You'll probably need to trim the holes a bit to make the slightly-larger momentary switches fit.

8.  In the pegboard bay, temporarily tape the sensors to the appropriate tanks (see the Instruction Manual for details about cutting the strips to proper length and to properly set each strip to the  appropriate tank type).  Then connect all blue wires together and tap them into the blue wire in the wiring harness.  Do the same for all of the black wires with the black wire in the harness.

9.  In the wet bay, make the connections described in the manual.  This means cutting the wires coming FROM the tanks and using the blue/black wires coming from the new sensors to connect to the wet bay display.

10. After deciding what lines ("old" sensor lines going from the tanks to the inside display) you'll use, connect them from the wet bay monitor to the corresponding place on the inside monitor.  (Again, READ the instructions!).

11. Inside, ensure that wires you connected to the wet bay display (that were "old" sensor lines going to the inside display) are now properly connected to the new inside connector.  There are four of them, plus another couple used for the new water pump switch in the new monitor.

12. Once everything's connected, test it.  Make sure that the sensor strips are pressed firmly against the tanks - the ENTIRE length of each strip.  You should see some sort of reading.  If your tanks are approaching empty (maybe 15% full or less), you may see a "0" on the display.

13. Finally, remove the adhesive from the back of the sensor strips and attach them to the tanks.  Leave about 1/2 inch from the top of the tanks to the top of the strips.  Once they're attached, use duct or gorilla tape to more firmly secure them.

14. Screw in (mount) your displays.  The inside one may be smaller than the original hole, so you may need a bezel to mount it to.  Make one by cutting something that will fit over the existing hole and can be screwed into the existing screw holes.  Before mounting, cut a hole in the new bezel that'll fit the new monitor.

I'm fully aware that a lot of detail about the wiring is missing from the above description.  You can look at the manual and figure a lot of it out.  The main thing I wanted to communicate is the general process to make it all happen and suggest that you do it in the same order that Norm used.

Since it's been installed, the SeeLevel II has worked really well.  It's nice to see a more detailed display of our tank levels.  Quite an upgrade!

And once more, a BIG THANK YOU to Norm MacLeod for sharing his time and his knowledge.  I learned a lot.