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I still would replace the brake pedal switch first.

The brake switch at the top of the pedal has more than one circuit in it. One may be gone. Does your cruise light go out when this happens or do you occasionally get traction control or stabilitrac errors on the DIC? I would replace the brake pedal switch it is cheap and see if it corrects the issue.

Open to Canadians?

see attached instructions trailer brake wiring.pdf

They changed the 8 bolt pattern in 2011, so anything early will do. Some RAM wheels are also the same bolt pattern. 8X6.5

Yes they will work

Is it giving any codes using a quality scanner? The code will tell you what might be wrong. My 2010 did this quite a few times over a month and then eventually the brake interlock would not let me start the truck and the brake lights weren't working all the time as it got worse. It was the brake light switch at the top of the pedal that went out and it fixed ALL my issues and was cheap to do myself. When is this happening and does it happen all the time or occasionally and check for any codes with a good scanner. This will help figure it out as it could be more than one sensor.

Unhook the wires from one and try the bell and the nest to see which one it controls and then the other one do the same. No harm should be done to either by doing this as long as you do not short the contacts on the transformer. The nest thermostat should be using the transformer built into the furnaces though. Maybe something else is using the second transformer like a garage door monitor or something similar? If neither of these transformers are for the door bell or the nest thermostats and you cannot get a reading off of them, I would disconnect them totally until you found out what they are for.

The second transformer looks like it is for a furnace humidifier (24V). Is there one on the furnace or maybe an electronic air filter? For the door bell, Both wires go into the bell box, but only one connects to the bell, the other wire goes to the door switch and then back to the front or rear terminal so that when the button is pushed the bell circuit is completed. Either of these transformers can be used for the door bell most likely, they just need to be wired correctly. Quick test is to attach one wire to transformer terminal from the transformer and briefly touch the other wire to the front or back terminals to see if the bell itself is working.

My 2010 Mexican CC is very good compared to the same US vehicles. I did not have the cost saving measures of the US ones that caused some issues. For example I got the proper back wall liner and thus NO noise like some made in the US where they tried a new liner (cheaper) that let in more road noise in the CCs that wasn't addressed until a few years later.

I used a can of stop leak on my 2010. It plugged the orifice tune within weeks and I had to replace the orifice and accumulator. It is still leaking about 5-6 oz, per year But thats OK because its all 12A. I ditched 134a when I did the repair.

On the GMT900 series a faulty brake pedal switch couls also cause this effect. Might be the same on a 2014.

more than likely low on refrigerant. It may have a slow leak, but, DO NOT use any sealer as it will definitely plug the orifice tube and lead to more costly repairs. Have someone check the level, at six years old that is more than likely the problem.

Could also be the brake switch at the top of the brake pedal going bad. Do your brake lights all work properly or flicker? My 2010 did this for a while and then the brake lights started acting up. Replaced the brake switch and it fixed both problems.

Dome light on a '12 is not canbus.