Washer-dryer combo will not start or advance; display shows dU and door remains unlocked

Safety first: Disconnect power before working on the door lock or control. Avoid forcing the door closed or open.

• 1. Check for mechanical jam: Inspect the door latch opening and gasket for clothing, coins, or debris preventing the lock from moving. Remove any obstruction and try again.
• 2. Verify door alignment: Gently lift the door while closing. If the door sags, hinges may be worn and preventing proper engagement with the lock. Adjust or replace hinges if needed.
• 3. Inspect door lock assembly: Access the lock from the front panel or boot. Look for broken plastic levers or signs of overheating. If the lock cannot move freely by hand (with power off), replace it.
• 4. Check wiring: Trace the harness from the door lock to the main control board. Ensure connectors are fully seated and wires are not pinched or cut.
• 5. Reset control: After inspection, reconnect power and attempt a cycle. If dU returns immediately, the lock switch may not be signaling correctly.
• 6. Replace door lock: Install a new OEM Speed Queen door lock assembly if the existing one is mechanically or electrically faulty.
• 7. Control board diagnosis: If a new lock and good wiring do not resolve dU, the main control board may not be reading the lock signal and should be tested or replaced by a technician.