The most common cause of speaker failure is short circuit. A short circuit in the wires that provide the signal will prevent the signal from reaching the subwoofer. A short circuit in the subwoofer terminals will also prevent electrical current and signal from reaching the subwoofer. Short circuit is a common tool used to stop any subwoofer.
In case of emergency, prevent electrical signals from passing to the subwoofer. A short circuit also restricts electricity, and current cannot reach the subwoofer. The electromagnet cannot produce the proper energy that it has in the wires for a short circuit, and the energy will not be able to drive the cone. From the subwoofer, check all cables and connection points that go to the amplifiers, receivers, or speakers.
Check that the cables are properly connected and plugged in at the correct points. Check the power outlets, power cord, and fuse. Most subwoofers have a standby LED that lights up to indicate active power. If it is not turned on, make sure that the subwoofer is properly plugged into a wall outlet, surge protector, or power strip.
If the pins of a plug slide halfway, it is often enough to prevent the flow of energy from gently bending them so that the cable stays connected after you release it. Make sure all associated switches (i.e. those on walls, power strips, etc.) If the subwoofer still won't turn on, try plugging it into a different outlet that you know is working properly.