Display shows E13 and the refrigerator may not respond correctly to temperature adjustments.

Safety: Disconnect mains power before removing the control panel or accessing electronics.

• Power cycle: Unplug the refrigerator for 5–10 minutes, then reconnect. This can clear temporary communication glitches.
• Inspect control panel: Check for signs of condensation, liquid spills, or physical damage around the display and buttons.
• Access the panel: Carefully remove the trim around the control panel (usually clipped or screwed). Gently pull the panel forward to expose the ribbon cable or wiring harness.
• Check connections: Ensure the ribbon cable is fully inserted and locked in its connector on both the display PCB and the main PCB (if accessible). Reseat connectors to improve contact.
• Dry out moisture: If moisture is present, allow the panel and connectors to dry completely before reassembly. Do not use high heat.
• Replace faulty panel: If buttons or touch areas are unresponsive or the display is erratic, replace the user interface/control panel with a Grundig-compatible assembly.
• Reassemble and test: Restore power and verify that controls respond normally and the E13 code is cleared.

If communication errors persist, the main control board may be defective and require professional replacement.