When I arrived, the customer explained their thermostat was going crazy. They had it set for 75 and woke up in the morning and it was set for 43°. I explained to the customer that everything looked and seemed good with it while I was there and offered to install a new thermostat. The Customers went ahead and decided to approve an estimate for a new thermostat. After installing the new thermostat, I tested their system and heat and cool modes. The system is operating properly in both. .