Search on
hunter rv thermostat on here and other RV forums and on google or other search engine. The Hunter is inexpensive, readily available, and very easy to wire in place of the standard Dometic ones.
There are all kinds of sites with instructions for this and it is very easy to do.
Here's one:
http://home.roadrunner.com/~morodat/hunter_install.html
Hint: I did this and never bothered to add the HI/LO fan switch. Since there is a single AC for our 36' fiver, I just let it run on LO all the time. Keeps the trailer plenty cool. (Might be an issue in the southern states, tho.)
__________________
'11 Cougar 326MKS loaded with mods
'12 Ford F250 SuperCab 6.7 PowerStroke Diesel
Amateur Radio: KD2IAT (146.520)
GMRS: WQPG808 (462.675 TPL 141.3)