Follow each step carefully.
Switch off the power to the outdoor unit at the circuit breaker.
Find the discharge pipe sensor on the outdoor unit, typically near the discharge pipe.
Carefully disconnect the wires from the discharge pipe sensor.
Turn on your multimeter and set it to measure resistance (Ohms).
Attach the multimeter probes to the sensor terminals.
Observe the resistance value displayed on the multimeter.
Reconnect the wires to the discharge pipe sensor securely.
Turn the power back on at the circuit breaker for the outdoor unit.