Two furnace thermostats need help

Chris Bryant hit it right on. We Xplorer owners are familiar with this set up. There should be a fan powered roof vent which will be connected to a thermostat. ON/OFF switch may or may not exist on the thermostat that is connected to it but once the fan is ON and spinning, you should be able to regulate the temperature that it will shut down when the setting is reached. You can confirm that the T stat is part of the fan circut by sliding the temp adjustment thru the setting incraments after you have the fan on. The switch should be both on. The one on the fan itself, off hi low and maybe med, and the on/off ON at the thermostat. The thermostat switch is to acivate the sensor for temp control. It needs to be in the off position when not usuing the fan as it will draw power and eventually kill the battery.