holding tank sensors location on my Miramar

[jbrosecity]

I was wondering if someone on the forum could tell me where my holding tank sensors are located on my Miramar.

2019 Thor Motor Coach Miramar 32.2

We have had a lot of trouble with the sensors on the grey water tank giving false readings. I have read up online about remedies for this problem and nothing has worked. We dump our tank, and it reads empty but as soon as a few gallons of water go down the sink drain, it immediately jumps to 2/3 full. I read this explanation:

"There is a negative tank probe installed at the bottom of the tank in the empty position. The remaining tank sensors are positive. As the content in the tank rises and makes contact with one of the positive tank sensors it completes the circuit which in turn illuminates that tank level reading at the monitor panel." Apparently when the tank is emptied the circuit is open - and if the 2/3 full sensor is gummed up, for example, as soon as some water is added to the tank and reaches the bottom negative sensor, this completes the circuit and it immediately would read 2/3 full.

AHHA. Since we have tried every kind of tank and sensor cleaner with no improvement, I want to replace my sensors. In order to do this, I need to know where they are located. I am hoping they are not in a spot which is too inaccessible.

Can anyone tell me where to find them?

[jbrosecity]

I have done everything possible to clean the inside of the tank. That is not the issue... it is almost certainly faulty sensors. I see many remarks on forums and youtube where people replaced ineffective or faulty sensors with Horst Miracle Probes which reportedly work much better.

I have purchased the replacements and have examined the underside and can't even SEE the holding tanks... All I can find is the fresh water holding tank in the large underbay just forward of the passenger side rear axle. My Allegro Bus had the black and grey tanks located there. But I just cant find them on the Miramar.

I am guessing that the tanks may be visible behind the sheet metal panel in the main plumbing bay indicated by the yellow arrows in this photo


http://www.wind-seeker.com/temp/plumbing_bay2.jpg

That panel looks like it can be removed by unscrewing a number of small square drive screws. Before I go removing that panel I had hoped to get some confirmation that the holding tanks and very possibly the sensors may be located behind that panel. Can someone confirm this for me? I have looked everywhere and it's hard for me to imagine they could be anywhere else, especially since the dump valve and the saniflush connection are located just below there.

Thanks for any guidance you can provide

[16ACE27]

Your gray tank is likely behind one of those partitions. The location of the tank should easily be located by following back the 1.5" drain pipe from the dump valve. There is a lot of space for tanks above the drive line but below the floor level. I suspect your black tank is directly below the toilet on the passenger side of the coach.

[jbrosecity]

I thought I would close out this thread with the final results - the sensors for both the grey AND the black tanks were readily accessible once the front sheetmetal panel in the plumbing bay was removed. I had to remove roughly a dozen square drive screws and the panel was removable in two pieces. I followed the instructions for the Horst sensors drilling new 3/8" holes and inserting the new Horst sensors and tightening the small nuts on each one, and connecting the respective wires from each OEM sensor. Sensors were pretty easy to install. The hardest part was replacing the sheetmetal panels and getting the holes to line up on the side tabs of each panel. But after a certain amount of groaning and swearing it all went back together.

I am happy to report that the new Horst sensors work perfectly and we have not had a false tank level reading since. Since my wife likes to a lot of laundry with our on board Splendide w/d, she is thrilled that she can now depend on the tank level readings on the touch panel. Kudos to the Horst folks!

[Beau388]

Originally Posted by jbrosecity

I was wondering if someone on the forum could tell me where my holding tank sensors are located on my Miramar.

2019 Thor Motor Coach Miramar 32.2

We have had a lot of trouble with the sensors on the grey water tank giving false readings. I have read up online about remedies for this problem and nothing has worked. We dump our tank, and it reads empty but as soon as a few gallons of water go down the sink drain, it immediately jumps to 2/3 full. I read this explanation:

"There is a negative tank probe installed at the bottom of the tank in the empty position. The remaining tank sensors are positive. As the content in the tank rises and makes contact with one of the positive tank sensors it completes the circuit which in turn illuminates that tank level reading at the monitor panel." Apparently when the tank is emptied the circuit is open - and if the 2/3 full sensor is gummed up, for example, as soon as some water is added to the tank and reaches the bottom negative sensor, this completes the circuit and it immediately would read 2/3 full.

AHHA. Since we have tried every kind of tank and sensor cleaner with no improvement, I want to replace my sensors. In order to do this, I need to know where they are located. I am hoping they are not in a spot which is too inaccessible.

Can anyone tell me where to find them?

Thor MC uses the "through the wall) type of sensors. There are 4 or 5 per tank depending on the factors and tanks size. On my water tank they are on the outside and easily accessible. Shown are the two bottom ones. The others are under the black shield. The orange pill is the integrater that determines the voltage to be sent to the display. Unless the tank's bottom is flat and the sides flat, the probes seem randomly placed. Only my black water is a cube and its probes are equally spaced and are on the backside of the tank. The gray water tank runs across the coach and is tucked up above the drive shaft so the sensors are between the side of the tank and the adjacent basement compartment. Etrailer sells shielded replacement sensors.