Installing Digital Thermostat to 4 Wire system

[Mr_Dave]

Good Day to you all.
First of all thank you for looking at my post.
After much research I fell like I need to start a new post to get some advice.

I have a 2015 Reflection by Grand Design 5th. Wheeler that has a basic Atwood Thermostat, and I would like to install a new Honeywell WIFI Digital thermostat in it's place.

There are just 4 wires coming out of the Thermostat right now. (Black red White & Yellow)

Can someone please let me know what I need to do for basic installation, and so I can still control the fan for the AC?

Thank you very much.

[TucsonJim]

Welcome to the forum Dave. Can you post the model number of the new thermostat and a wiring diagram from the installation instructions? We might be able to guide you with that info.

Jim

[Mr_Dave]

Good afternoon Jim.
Thank you for your reply.
I haven't purchased the new thermostat yet because I am not sure if I would still be able to adjust the fan speed depending on the outside heat. I read somewhere recently that the new Honeywell WIFI Digital thermostats work, but without to option to adjust the speed. If you know if this is a possibility, or perhaps recommend another product I would greatly appreciate it. Thanks again.

[offtohavasu]

If you're referring to a WiFi home thermostat it won't work, without several mods. Check youtube for modifying the fan speed switch. There are several out there.

Then there's this. WiFi home thermostats require the "common" wire off of the transformer from the furnace. This supplies the thermostat with 24v power. You won't find this in the RV application. You would need to power the thermostat from a plug in 24v transformer, meaning the only time it will work is if you're on shore power, or you get an inverter.