The fourth bunker is built against the air raid shelter and consists entirely of masonry. In this garage (depot) a searchlight and the associated generator, which provided the power supply, were stored.
The searchlight had a diameter of 60 cm and had a considerable range of 4,000 meters horizontally and 7,000 meters vertically. The searchlight was deployed as soon as an attack by enemy ships or aircraft was imminent, whereby the searchlight was needed to illuminate them. The searchlight was operated by two soldiers.
Between the garage and the platform is a cobblestone path over which the searchlight could be pushed by the soldiers to the desired spot. From this cobblestone path, a concrete track ran in a wide bend to the roof of the type 504 bunker (bunker 3), the highest point of the complex (now the checkpoint). From this spot, the searchlight could be used at a 360 degree angle.