Display shows “18”; opener operates but light does not turn on or off correctly.

Safety first: Unplug the opener and allow the bulb to cool before handling.

• Check bulb: Install a new bulb of the correct wattage and type recommended by Marantec (often LED or incandescent within a specific watt limit). Avoid high‑wattage or incompatible LED bulbs.
• Inspect socket: Look for corrosion or burned contacts in the light socket. Clean lightly or replace the socket assembly if damaged.
• Check wiring: Verify the two wires from the control board to the light socket are intact and firmly connected.
• If light still inoperative or stuck on: The light relay or triac on the control board is likely failed. Replace the Marantec control board.