Microwave will not start at all; display is on and keypad responds, but pressing Start does nothing

Safety: Unplug the microwave before any disassembly.

• Check door indication: Many Whirlpool models show a 'door' icon or message if the door is not sensed as closed. Open and close the door firmly and try again.
• Test other functions: See if the vent fan or surface light (on OTR models) works. If they do, power is present and the issue is likely with door sensing or control logic.
• Inspect door latch and switches: With the cabinet removed, check that the latch hooks fully engage the door switch levers. Replace any broken latch or faulty switch.
• Check keypad: If only the Start button is unresponsive, the keypad membrane may be failing. Replace the control panel assembly.
• Control board: If door switches and keypad are good, the main control board relay or logic may be defective and require replacement.