Here is the location of the fuse box and the relay panel of the Opel Astra J.

On your Opel Astra J, the electrical protections are not concentrated in a single location: generally, you will find a module in the engine compartment, an access point in the cabin, and, in some configurations, an additional compartment in the trunk. To work safely, turn off the ignition, remove the key, and work with dry hands; if you need to remove multiple fuses or work near wiring, it is wise to disconnect the negative terminal of the battery. In the engine compartment, the fuse/relay box is identifiable as a black box with a cover, located near the battery. By opening the cover, you gain access to the module with fuses and relays: often on the back of the cover, you will also find the reference diagram and, in some cases, a fuse extraction tweezers. To close it again, make sure that the cover fits snugly along the entire perimeter to avoid infiltration and oxidation. In the cabin, access is located under the dashboard/side of the instrument panel, near the pedal area and the diagnostic port: you need to remove the small cover panel to reach the fuse group. Here, it is advisable to work with a plastic lever to avoid marking the finishes and without forcing the clips, as the hooks can break easily. If the vehicle is also equipped with a rear compartment, the module can be accessed from the trunk behind a side cover: lift or unclip the access panel to reach the area dedicated to the rear fuses/relays. After completing your work, always reassemble the panels, ensuring that no wires are pinched and that the covers are properly seated, then check that the affected device functions correctly and that no warning lights appear.