is there any kind of coverage for a fuse box on our 2012 Chevy Impala

Interior fuse box or under the hood power dist. center? The first would be covered under a bumper-to-bumper warranty, the latter under a powertrain warranty, and if you're out of warranty you're SOL. Having replaced one myself, I can suggest that someone with automotive electrical experience can do it and it's not a tough job at all, just have to be meticulous, but someone who has never done it, best to leave it to a pro, cuz once your tear it apart you're not going anywhere until it's fixed. But with your car being only 5 years old, I would really argue and negotiate with the dealer to get it done, they might extend you a courtesy.

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