@heretofixitems remove the ear cushion and see if that allows you to remove the driver (speaker) that should reveal the circuit board and switch. See if it has become dislodged. If it is broken/broken it'll be difficult to find a direct replacement. you may have to do an online search for a microswitch that will fit the dimensions of yours. To remove the cushions use something like [https://www.youtube.com/watch?v=AipRvTA07CY|this video] to get to it. After that post pictures with your QUESTION if stuck. [guide|21499|Adding images to an existing question - iFixit Repair Guide|new_window=true]