Heat and Air Condition run at the same time

[Padre]

Hi all, long time lurker 1st time poster...
2017 19', in Playa Bonita, Mexico, it was a little chilly, so I decided to put on some heat. What followed, was both heat and A/C started running.
Has anyone ever experienced this?
Both systems have worked correctly prior to today. The thermostat does not offer an "Auto" mode now, perhaps it needs a reset.
I tried several times today hoping it would fix itself, so much for wishful thinking...
Thanks!
Padre aka Paul

[CADreamin]

You might try disconnecting from shore and seeing if that helps (kind of like unplugging your computer ... ). You can also reset your battery disconnect. Be sure your fan is on "auto" - but it sounds like you know that. (When we were having our fan issue the first time and I switched off the two top breakers, somehow our thermostat reset because, when we turned the heat on the first time after that, the fan had reset itself and we had both heat and A/C.)

[C&G in FL]

Originally Posted by Padre

Hi all, long time lurker 1st time poster...
2017 19', in Playa Bonita, Mexico, it was a little chilly, so I decided to put on some heat. What followed, was both heat and A/C started running.
Has anyone ever experienced this?
Both systems have worked correctly prior to today. The thermostat does not offer an "Auto" mode now, perhaps it needs a reset.
I tried several times today hoping it would fix itself, so much for wishful thinking...
Thanks!
Padre aka Paul

The auto mode is in the fan setting. If it is a Dometic thermostat, push the on button once. Make sure the fan speed was not inadvertently set to low or high. It must be on auto to correct what you are experiencing.

[Eggscape]

Here is a video...if that helps. https://youtu.be/RjlRayhj-44

[Padre]

That did it, thanks folks. I guess I never did have a clear understanding of hi/lo/auto.

[padlin]

Originally Posted by Padre

That did it, thanks folks. I guess I never did have a clear understanding of hi/lo/auto.

I still don't, when it malfunctions I fiddle with the fan till it does what I want.