Replace Dometic with Honeywell Thermostat
After putting up with 5 degree temperature swings I decided to figure out why I was constantly going from hot to cold and back again. As the temps outside I wanted them more constant inside. It all came down to the thermostat. The Dometic analog (with temp slide) was definitely the problem. Spending was a consideration - I wanted a good thermostat but with features.
I finally settled on the Honeywell 5.2 Programmable. Perfect for what I wanted.
I researched a few forums and also the manufacturers recommendations. My system is a Suburban LP furnace and Dometic roof mounted AC. I used the color coding of Red (cap it off), Yellow to Y (cool), Brown/Blue both to G (fan - high speed), White to W (furnace), Green to RC/RH.
In my case I also an Orange Lead (I capped it off - it is to the warmer in the AC unit - an added feature).
It took 30 minutes. Time well spent. The unit runs a little more but the temp swing is gone. I have a 1 (at most 2) temp change before the unit comes one.
Best of all - it is programmable. I now wake up to a warm (or cool) unit. No more fiddling with the old slide and end up hot and cold.
The big NOTE that anyone who wants to make the same change - the thermostat must be able to work with 12V systems.