Upon arrival, I identified a faulty heat sequencer as the root cause of the system's malfunction. This issue caused the electric heat strips and lower motor to operate continuously, even when the thermostat was set to off. I replaced the defective heat sequencer to rectify the problem. Following this, I conducted a thorough check of the refrigerant charge to ensure it was at optimal levels. After these interventions, the system was fully functional, providing the customer with reliable cooling. The system is now operating as intended, with the thermostat effectively controlling the heating and cooling cycles.
