Found heat strip not coming on when thermostat was calling for heat. No voltage on the proper wires at air handler. Went ahead and jumped out some wires at the air handler to verify that heat strips actually work. Heat strips came on. Check programming on thermostat to verify everything was programmed properly And that it was wired correctly. Found the thermostat to be bad. Replaced thermostat with new thermostat and tested strip heat no other issues found with the strip heat. Found defrost board to be bad. We’re going to replace coil sensor and defrost board under warranty. Should be in Friday afternoon if not Monday.