System Diagnosis
External outdoor temperature sensor fault (open/shorted).
Troubleshooting guide for the American Standard AC and Heat Pump system fault Red 13 Flashes.
Sensor values that do not match the operating condition or drift when the harness is moved.
A control board issue can look like a failed sensor if the reference voltage or connector is unstable.
ACLogics has guided diagnostics for 36 American Standard fault codes and asks the right questions to narrow it down.