Swapped the thermostat from the front to the back and fixed the issue. I ordered a new one from Amazon for less than $30 and it came in today. Now that both A/C units have been cleaned (Both condenser and evaporator coils) and new capacitors installed (Supco SPP6 starting cap and GE Genteq 35/5 uf for the Run/Fan)and new insulating foam under the shroud; with both running I can get the coach quickly to 70 degrees inside while 95 outside in direct sunlight. The units are also both MUCH quieter. Not to bad for 16 year old units that have probably never been serviced.