Trane air conditioner shows F1 and may not respond correctly to thermostat settings; temperature swings are noticeable.

Safety first: Turn off power to the indoor unit before opening the control compartment or thermostat.

• Check thermostat: If using a Trane communicating thermostat, ensure it is mounted away from direct sunlight, supply vents, and exterior doors. Relocate if necessary.
• Inspect sensor wiring: For systems with a remote room sensor, verify the sensor wires are intact and firmly connected at both the sensor and control board.
• Compare temperatures: Use a reliable thermometer near the thermostat to compare readings. A large discrepancy suggests a bad sensor.

Persistent F1 errors usually require replacement of the room sensor or thermostat with a compatible Trane component.