Diagnosis
The user interface control board has likely failed. The hum is the inlet valve getting power, proving main control is alive. This is a common failure point.
How to Fix It
You must replace the user interface (UI) board. Part number is WD21X25633. Disconnect power at the breaker. Remove the inner door panel to access the board. Swap the connectors to the new board. Reassemble and restore power.
If That Didn't Work
Verify 120VAC is reaching the UI board from the main control board. If power is present and the new UI is dead, the main control board (WD21X25634) is also faulty.
Heads Up
Always disconnect power before opening the door panel. The new UI board may require a calibration cycle. Run a quick rinse cycle first to confirm operation.