Washer powers on but will not start any program; Start button unresponsive.

Safety first: Unplug the washer before removing the control panel.

Step-by-step checks:

• Check for child lock: Many Grundig washers show a key symbol when child lock is active. Deactivate by holding the specified button combination (refer to user manual, often pressing and holding two buttons for several seconds).
• Test other buttons: If only the Start button is unresponsive, the switch may be faulty. Remove the control panel and inspect the tactile switch on the PCB.
• Inspect ribbon cable: Ensure the cable between UI and main PCB is firmly connected and not damaged.
• Replace UI board: If multiple buttons fail or the panel is intermittent, replace the user interface board.