Cordless vacuum will not power on at all when the power button is pressed, no lights on the handle or battery indicator.

Safety first: Always remove the battery pack from the vacuum before opening any covers. Do not short battery terminals.

• 1. Verify battery charge: Remove the battery pack from the vacuum and place it on the Siemens charging dock. Confirm that the charger LEDs illuminate and that the pack charges for at least 30–60 minutes. If the charger shows no lights, test with another outlet.
• 2. Check battery seating: Reinsert the battery pack firmly until you hear/feel a click. Many Siemens cordless models (e.g., QX, VSC series) will not power on if the battery is not fully latched.
• 3. Inspect power button: With the battery removed, press the power button repeatedly. If it feels stuck or has no tactile click, debris may be lodged. Clean around the button with a soft brush and a small amount of isopropyl alcohol on a cloth (never pour liquid into the vacuum).
• 4. Hard reset: Remove the battery for 5 minutes. Press and hold the power button for 10–15 seconds (battery removed) to discharge the control board. Reinstall the battery and try again.
• 5. Internal wiring/PCB check (advanced): If still dead, remove the handle screws and carefully open the housing to access the main control PCB. Look for burnt components, loose connectors, or broken wires from the battery terminals to the PCB. Reseat all connectors. If there is visible damage or a burnt smell, the PCB should be replaced rather than repaired.

Stop and call a professional if you see swollen, leaking, or damaged battery cells, or if you are not comfortable opening the handle assembly.