Vacuum will not power on when the power button is pressed; battery LEDs remain off even after charging.

Safety first: Disconnect the charger from the mains and remove the battery pack from the vacuum (if removable) before any inspection.

• 1. Check charger and outlet: Plug the Grundig charger into a known-good outlet. Verify the charger LED comes on. If the charger LED is off or flickers, test with another compatible charger if available.
• 2. Inspect battery pack: Remove the battery pack from the handle or base. Check for burn marks, swelling, or cracked housing. Clean the battery contacts with a dry cloth; do not use liquids.
• 3. Reseat battery: Reinsert the battery firmly until it clicks. Loose battery rails or latches on Grundig cordless vacuums can prevent contact.
• 4. Test power button: With the battery installed, press and hold the power button for 3–5 seconds. If there is still no response, lightly wiggle the button while pressing; if it feels loose or jammed, the switch or upper handle PCB may be faulty.
• 5. Inspect handle terminals: Look into the battery bay on the vacuum. Ensure the metal terminals are not bent, recessed, or corroded. Slightly bend them outward with a non-metallic tool if they are not making firm contact.
• 6. If still dead: The main control PCB or power button assembly is likely defective. Replacement requires opening the handle housing and should be done by a qualified technician to avoid damage to the Li-Ion circuitry.