Passport I/O in salon not showing correct room temperature

[rappja]

Sorry for starting a new thread on this subject. I posted before, and wanted to reply to answers, but I couldn't figure out how to post photos in a reply.
The issue is on my 2019 RT-31CB LE. The Passport I/O control for the a/c does not show the correct room temperature in the salon. So, when I use it for heating, the controller continuously shows a temperature like 62 or 64. Therefore, the thermostat never shuts the heater off, and the salon gets too hot.
I believe the trouble is with the placement of the thermostat sensor, which I found attached to a bracket about 1/2 inch from the cold copper coils. This is located in the coffin berth at the foot of the mattress. Someone suggeted pointing a hair drier at the sensor to heat it up. When I did that , the temperature shown at the controller went up, and the unit shut down as it's supposed to.
The factory mounting of the sensor seems to be intentional, as it is mounted on what looks to be a bracket specifically designed to hold it. However, it makes no sense to me, as the temperature there will always be cold, and is not reflective of the salon temperature.
I believe the solution would be to move the sensor to the area of the intake grill which is located just aft of the steps that go down to the forward cabin. There is enough wire there to move it to that position.
However, There are 2 problems. One is that I am hesitant to move the sensor, as it seems to be mounted where it is intentionally. Second, I am not sure what the cylindrical box attached to the inside of the "grill" is for (see picture below, which shows the top of the grill after it was removed form the wall). There are electrical connections, and I hear what sounds like a fan in there. Also, 2 rubber hoses are attached.
Can someone tell me what this is? The intake for the a/c is in the coffin, and has a difficult to clean dust filter.
Has anybody else had to move the sensor? I can't believe I am the only one with this problem. I must be missing something.
The second picture shows the type of Dometic a/c this is, if that's important.
Thanks

 

[Mastercraft]

I have a 2017 R29 NW edition, so mine is different for photo 2. Photo one is my heater that can only run if the engine is running. It has a three speed switch at helm, no thermostat. Hoses are antifreeze radiator fluid that provide heat like a typical car. Fan blows air over the rectangular grill radiator fins.

 

[rappja]

Thanks for the info about the heater. I think I get that part now.
I still don't know what to do about the thermostat sensor, but I get that you don't have one.
BTW, I would have liked to reply with another picture attached. Do you (or anyone else) know if there is an option to attach a picture in a reply?
Thanks again

 

[mikee30]

Thanks for the info about the heater. I think I get that part now.
I still don't know what to do about the thermostat sensor, but I get that you don't have one.
BTW, I would have liked to reply with another picture attached. Do you (or anyone else) know if there is an option to attach a picture in a reply?
Thanks again

I looked at both units on my R31. Both had the remote sensor tucked in near the coil. Too cold down there in the winter to represent a good ambient temp in salon and v berth. I moved both away from the compressors and as far into the rooms that the cable would allow.

 

[rappja]

I looked at both units on my R31. Both had the remote sensor tucked in near the coil. Too cold down there in the winter to represent a good ambient temp in salon and v berth. I moved both away from the compressors and as far into the rooms that the cable would allow.

Thanks for the info!
That was my plan exactly.
Two things, though. Yesterday, I spoke to my local Dometic dealer, who advised me that our presumption is correct (it's too cool in that location for the unit to operate properly in the winter) and that his solution is simply to take out the sensor by unplugging it from the electrical control box.
He claims there is a sensor in the Passport I/O controller that takes over when the other sensor is removed.
This seems a little weird to me, but I'm going to try it when I get back to the boat. As you know, it's hard to reach the electrical box, so I may not be successful. I'll post once I try it.
The other thing is why it was put there to begin with, and why one doesn't hear more about it from other owners.
All this feels a bit like the twilight zone.

 

[rappja]

I notice you attached a picture to your reply. Can you tell me how you did that? I don't see any attachment icon when I post a reply.

 

[mikee30]

I notice you attached a picture to your reply. Can you tell me how you did that? I don't see any attachment icon when I post a reply.

I was going to unplug the cable from J3 on the controller board but I didn’t have time to check the manual as to whether I needed to tell the system about it, so I haven’t yet.
As for the photo upload, it’s the 4th icon from the left at the top of the reply window. I uploaded a picture of my thermostat to show you the ambient air sensor that’s used instead of the remote sensor. It’s the raised area below the temp read out.