Another possibility is that the window regulator is damaged. The window regulator is a mechanical component that raises and lowers the windows. If the window regulator is damaged, it will not be able to raise or lower the windows, and they will remain stuck in one position.
Finally, it is also possible that there is a problem with the wiring between the relay switch and the windows and sunroof. If the wiring is damaged, it will prevent power from reaching the windows and sunroof, and they will not be able to operate.
To determine which of these components is causing the problem, you will need to inspect the relay switch, window regulator, and wiring. If you are not comfortable doing this yourself, you can take your vehicle to a qualified mechanic who can diagnose the problem and perform the necessary repairs.
Here are the general steps on how to locate the relay switch for your BMW 318i:
1. Open the hood of your vehicle.
2. Locate the fuse box.
3. Remove the cover of the fuse box.
4. Find the relay switch for the windows and sunroof.
5. The relay switch is usually located in a prominent position in the fuse box, often near other electrical components like fuses. It may be labeled with a symbol like a window or a sun.
6. Inspect the relay switch for any signs of damage, such as discolouration or cracks.
7. If you suspect the relay switch is faulty, you can try swapping it with another relay switch in the fuse box that has the same part number.
8. If the windows and sunroof start working again after swapping the relay switches, then you have found the faulty relay switch.
9. Replace the faulty relay switch with a new one.
10. Close the cover of the fuse box and replace the hood.
Remember that these are general steps and the exact location and procedure for accessing the relay switch may vary slightly in your specific BMW 318i model. It's always best to consult your vehicle's owner's manual or seek assistance from a qualified mechanic if you are not confident in performing these tasks.
