Thermador Hood Error Code Three speed LEDs blinking

When all three speed selection LEDs blink simultaneously on a Thermador hood, the control system is signaling a heat sensor protection fault. The heat sensor is a thermistor or thermal sensing element integrated directly into the input board assembly. This sensor continuously monitors the internal temperature of the hood electronics and, when it detects an out-of-range or open-circuit reading that indicates sensor failure, the control logic halts normal operation and triggers this blinking pattern as a fault indicator.

The critical detail with this fault is that the heat sensor is not a separately serviceable component. It is embedded within the input board itself and cannot be replaced independently in the field. This means the diagnostic path skips individual component testing and goes directly to input board replacement. A damaged sensor could result from prolonged heat exposure from cooking, electrical surge damage to the board, or simple component failure over time. Because the sensor circuit is integral to the board, any loss of continuity or signal from the sensor element renders the entire board non-functional for safe temperature monitoring.

Once the input board is replaced, the fault condition is cleared and normal hood operation is restored. There is no reset procedure that will resolve this error because the underlying hardware is physically compromised. Attempting to operate the hood indefinitely in this fault state is not recommended, as the heat protection feature will be inactive and the hood electronics could be exposed to thermal damage without the safeguard functioning.