Cordless vacuum will not power on, battery LEDs remain off even when pressing the power button

Safety first: Turn the vacuum OFF, remove the battery pack from the handle or base, and disconnect the charger from the mains before opening any covers.

• Check battery seating: Remove the battery pack (on many Medion cordless models it slides or clips out of the handle). Inspect the contacts for dirt, corrosion, or bent pins. Clean gently with a dry cloth and reseat firmly until it clicks.
• Test with charger: Insert the battery into the vacuum and connect the charger. If no LEDs light on the battery or vacuum, try a known-good outlet. If still dead, the battery pack or charger may be faulty.
• Check power switch: With the battery removed, press the power button repeatedly to clear any mechanical sticking. Inspect around the switch for debris. If the switch feels loose or does not click, the switch assembly may be defective.
• Inspect wiring (advanced): If you are comfortable with basic disassembly, remove the handle screws and gently open the housing to inspect the wiring harness from the battery contacts to the main control PCB. Look for loose connectors or broken wires and reseat any loose plugs.
• When to stop: If the vacuum still does not power on with a known-good battery and charger, the main control PCB is likely faulty and should be replaced by a qualified technician.