Why are the ford focus rear speakers not working?

If the rear speakers aren't working on Your Ford Focus, an obvious reason is that You've blown the speakers. If You've been playing incredibly annoying "music" of the urban variety in a parking lot in South Dakota at 3 am, then, frankly, I'm glad Your rear speakers finally went out, because You deserve it. But if that's not what You've been doing, and You're pretty certain there's no reason for both of the speakers in the rear to have blown, the next obvious thing is the speaker fuse. Check that relay to see if it's been tripped. Another "Oh, yeah" type of resolution here is checking the Fader settings. What happens if You fade all the way to the rear Sometimes this gets toggled, so if it's that, You'll facepalm, and then go on about Your now full-speaker listening life. None of that flying If You have a spare speaker somewhere, You can check the loom at the rear of the headunit to probe the terminals with the speaker cable, and that'll let You know if it's actually sending Audio to the rear; all things being equal, it's starting to point towards an issue with the radio itseLFAt this point.