An analog RV thermostat can be replaced with a Digital Hunter
part number 42999(B) or 42995 to provide tighter temperature control in
heating and cooling modes. The hysterisis program for the Hunter
thermostat is +/-1 degree of set temperature, and also provides a
readout of ambient temperature. The Hunter unit can be
from Wal*Mart for about $20.
I have also tested the programable Lux TX500 in my RV with the
same positive results. The Lux TX500 is available in many
Download the installation instructions from the link below for complete details. Credit for the original concept and details of the Coleman modification is given to Alan Paskey. Les Adams further developed this concept to work with the Dometic A/C and Atwood furnace.