On our last trip out, we needed the furnace one morning and when the digital thermostat was moved to the "furnace" position, both the heater and air conditioner came on at the same time. After several failed tries to get just the heater, I turned the air conditioner off at the breaker panel and the heater worked fine. On previous trips, each unit has worked independently just fine.
Anybody have a clue as to what may be the problem?
