Bosch Dishwasher Error Code F24

F24 on a Bosch dishwasher indicates a heating relay contact fault. The control board has detected 120 VAC at terminal ST5 on the electronic board when the heater relay is supposed to be off. This typically means the relay contacts have fused together or there is a wiring or connector issue causing unintended voltage in the heater circuit. The dishwasher will not run normally until the fault is resolved.

No, you should not continue running the dishwasher while F24 is active. The fault indicates the heating element circuit may not be controllable, meaning the heater could potentially run when it should be off. This creates a risk of overheating, and the machine is designed to stop operation to prevent that scenario. Discontinue use until the fault is diagnosed and repaired.

Repair costs depend on which component has failed. If the issue is corroded connector pins that can be cleaned or a connector that needs replacement, costs could be in the range of $20 to $80 for parts. If the heater relay or control board requires replacement, parts alone typically range from $80 to $250 or more depending on the specific board, with labor adding $100 to $200 if a technician is hired.

Some parts of the diagnosis are accessible to a knowledgeable DIYer, such as inspecting the relay output connector for corrosion and cleaning the pins. However, confirming whether the relay contacts are fused and testing for 120 VAC at board terminal ST5 requires a multimeter and comfort working around live voltage in an appliance. If the relay or control board needs replacement, those repairs are within reach for experienced DIYers but carry risk if you are not familiar with appliance electrical work.

A reset may temporarily clear the fault code display, but it will not fix the underlying hardware problem. If the relay contacts are fused or the connector is corroded, the fault will return as soon as the dishwasher attempts to run a wash cycle and the board checks the heater relay state again. A lasting fix requires physical inspection and repair of the relay or connector.