Dometic Cool Cat E2 error code

[folivier]

2011 Roadtrek 210 Popular on Chevy chassis.
After a short trip where we used the heat pump with no problems, got back and plugged in to 30 amp where I store it. Turned on air conditioner, set it at 84º and left for 4 hours. When I returned the fan was blowing but it was about 95º inside so it was not cooling. The thermostat was flashing the set point and E2. This error code is listed as: E2 *Open circuit or out-of-range indoor temperature sensor. All heat , cool, and de- humidify operations will be locked out. Manual fan operation will continue.
I turned off battery switch and shore power for a couple minutes then turned all back on. Thermostat was still showing E2. It is the Dometic Single Zone LCD thermostat #3313193.XXX
It sounds like something in the thermostat is not working but I can't find anything on how to fix it.
Do I need to replace the thermostat? If so should I replace it with the same model (if I can find it) or are there any others that would work with the cool cat?
The AC was working properly previously.

[hbn7hj]

Probably work perfectly after cooling over night. If not, a new one is $50 on Ebay or Dometic dealer.

[GroupB]

Could possibly be a sticking reversing valve, and the thermostat is working properly. My understanding is that the valve's default position is the heat mode. The thermostat may be telling it to switch, but it's not moving.

I think a new thermostat makes sense as it could be an easy fix, but if it is the reversing valve, the problem may immediately or randomly occur again.

My reversing valve would randomly stick so I replaced the Cool Cat with a window A/C.

[folivier]

I'll check it out later today when I can get back there.
I'll also start searching here for replacement units in case the A/C is bad. If I have to pull the unit out I'll probably just replace it with a window A/C.

[folivier]

You were right hbn7hj. It worked this morning. I left it on and will check on it later today.
Any thoughts why it showed the error yesterday and today is ok?
I hate intermittent problems.

[hbn7hj]

Originally Posted by folivier

You were right hbn7hj. It worked this morning. I left it on and will check on it later today.
Any thoughts why it showed the error yesterday and today is ok?
I hate intermittent problems.

Yep. The thermostat placement makes it vulnerable to direct sun on that side of the coach. It can get much hotter than the interior air. I put a 3/8” piece of styrofoam behind it to insulate it more from the outside heat.

[folivier]

The sun was on that side and ambient temp was 85, inside was 95. It had been closed up for a couple hours. I'll see about adding some insulation on that wall. Thanks!

[hbn7hj]

Just an opinion but if the Dometic Cool cat fails the best course of action is to replace it with a Dometic Cool cat.