There are a few different things that can cause a solenoid to click. One possibility is that the solenoid is not getting enough power. Another possibility is that the solenoid is faulty and needs to be replaced. Finally, there could be something blocking the path of the solenoid's plunger, preventing it from moving freely. If you suspect that your solenoid is clicking for one of these reasons, you should have it checked by a professional to ensure that it is functioning properly.