Vacuum will not start unless the charger is connected, and stops immediately when unplugged.

Safety: Unplug the charger and remove the battery before further checks.

• 1. Check battery indicator: Press the battery test button (if present). If no LEDs light, the pack may be open or fully failed.
• 2. Try another battery: If available, test the vacuum with a known-good Siemens battery. If it works normally, your original pack is defective.
• 3. Inspect contacts: Ensure the battery terminals are clean and not recessed or damaged.
• 4. Do not attempt internal repair: Internal fuses and BMS components are not user-serviceable. Opening the pack is dangerous.
• 5. Replace battery pack: Obtain a new genuine Siemens battery pack. Recycle the old pack properly.

Running the vacuum only from the charger is not intended and can overload the charger; always use a healthy battery pack.