How Can I Check If My Stock Subwoofer And Amplifier Still Works?

[flipstyle808]

I have change all my door speakers and are working great

So how do i do this?

[RDM]

Do you hear the subwoofer playing? If not, put any known working speaker in it's place temporarily, does it work? If so, the amp works, subwoofer doesn't. If not, neither works.

Pretty obvious really.