I would like to bring to your attention an issue I experienced with the Dynon Pitot Heater Controller, P/N: 100640-000, installed across my fleet of 6 aircraft. The problem led to the controller becoming unserviceable (U/S).
Problem Description:
When the pitot heater switch is OFF, the EMS Debug Data still shows 5 volts, indicating the system believes the pitot heater is ON—even though it is not physically heating. This behavior was consistent across multiple aircraft in the fleet.
System Configuration:
My pitot heater circuit is composed of the following components:
10 Amp circuit breaker switch
Voltage converter (24V to 14V)
Dynon Pitot Heater Controller (100640-000)
Pitot Tube
Troubleshooting Performed:
Checked and verified all wiring continuity from switch to controller.
Ground connections were thoroughly inspected and confirmed to be secure and properly bonded.
Voltage readings at each stage of the circuit were within expected parameters.
No physical damage or corrosion found on connectors or wiring harnesses.
Resolution:
After replacing the Pitot Heater Controller (100640-000) with a new unit, the issue was completely resolved:
With the switch OFF, EMS Debug Data now correctly shows 0 volts.
System behavior is now consistent with switch position.
Pitot heater functions as expected when activated.
Request:
Please advise if this is a known issue or if further diagnostic steps are recommended to prevent future occurrences. As this failure occurred across multiple units in the fleet, I suspect a possible controller-level fault.
And why this happen
Problem Description:
When the pitot heater switch is OFF, the EMS Debug Data still shows 5 volts, indicating the system believes the pitot heater is ON—even though it is not physically heating. This behavior was consistent across multiple aircraft in the fleet.
System Configuration:
My pitot heater circuit is composed of the following components:
10 Amp circuit breaker switch
Voltage converter (24V to 14V)
Dynon Pitot Heater Controller (100640-000)
Pitot Tube
Troubleshooting Performed:
Checked and verified all wiring continuity from switch to controller.
Ground connections were thoroughly inspected and confirmed to be secure and properly bonded.
Voltage readings at each stage of the circuit were within expected parameters.
No physical damage or corrosion found on connectors or wiring harnesses.
Resolution:
After replacing the Pitot Heater Controller (100640-000) with a new unit, the issue was completely resolved:
With the switch OFF, EMS Debug Data now correctly shows 0 volts.
System behavior is now consistent with switch position.
Pitot heater functions as expected when activated.
Request:
Please advise if this is a known issue or if further diagnostic steps are recommended to prevent future occurrences. As this failure occurred across multiple units in the fleet, I suspect a possible controller-level fault.
And why this happen