I would have to agree with tjkj2002, I had the same issue he did. Also, as for the tensioner not having a part in the failure, wrong. Think of it this way, the tensioner's job is to keep proper tension on the belt thus even preasure on all pulleys, a bad tensioner that does not do this, is like walking your dog on a leash, and jerking the leash on his neck repeatedly. Now would it be covered under the repair for the tensioner, no. If it was a warranty repair, yes. So they are related, but unfortunately not covered as the same repair.
As for labor, that is a rip off, but pretty average for a dealer, they are better than every one else afterall

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I would do the repair myself, not that hard, unless you do need to replace the compressor, then you have to worry about reclaiming and refilling coolant gas, whatever DC uses.