98 expedition, eddie bauier edition. Has the mach audio system. Subwoofer in the back panel not working. amp or speaker u think. we bought it used, and no workie. Person we bought it from I know didn't crank it up to blow this stuff. wiring problem maybe? checked all fuses and non blown. Also, the back wiper just stopped outa the blue. did work the first day we got it. I can careless about this but the wife is asking me to fix. hah. btw, checked fuse there too, not blown. thinking maybe the relay in the back, or possible motor.