Domestic Thermostat Not Responding Correctly


I have a Heartland Road Warrior. I went to turn on the A/C yesterday and could not get the thermostat to kick the A/C on while in Auto (A/C) mode. When I turned the A/C on and used Low or High it came right on. Fast forward to night time and I went to turn on the furnace. I could not get the furnace to kick on when selecting furnace on the thermostat. When I tried to select low or high like I did to turn the A/C on, but with Furnace selected the air unit kicked on.

Any suggestions? Thank you for your help in advance.



Staff member
Hi Brian,

First, when the FAN is set to HIGH or LOW, the A/C blower runs continuously, whether the thermostat is set to COOL or HEAT. So when trying the A/C, you had the blower running, but perhaps no compressor. When trying the HEAT, again you had the A/C blower running, but not the furnace.

Have you fired up the furnace previously using that same thermostat? Only 1 thermostat controls the furnace.

And of course, the thermostat will only call for A/C or Furnace to run when there is at least a 2 degree difference between your set point and the air temp at the thermostat.

What year is your Road Warrior? Older units the thermostat connects to a control box above the A/C air return. A problem in either the thermostat or in the control box could explain failure of both A/C and Heat.



Thank you for your reply, it was very helpful.

It has been a while since we used the furnace and I forgot that this was actually just tied to one of the thermostats. The front thermostat (in the bedroom) controls the furnace and that worked great once I set that correctly.

As for the HVAC (middle one). I did a reset on the thermostat, then I turned it on (auto) and it kicked right on and ran fine all day yesterday.

Thank you again for your help.



Well-known member
Kinda random thought but it may help someone, I found when the battery dies on the camper (which it shouldnt, but when an accident occurs and it does) the brown out that results scrambles the thermostats. in those cases I found i need to perform the reset procedure on the thermostat to get it going again.