I went through the same thing. About $100 bucks and about 10 min. to solve what is an expensive PITA tearing $35-40 belts every 5k.
The tensioner goes bad and rocks back, allowing the belt to run around the rear of the AC pulley, eventually tearing the edge and v-rib belts peels in strips. Those flinging strips can hurt wiring.
Geno's has a good price as does PEP BOYS for a genuine Dayco part.
Mine was doing so i replaced the tensioner cause it was in bad shape, still did after that, and tracked it down to a bad idler pulley. Didn't have to track too far, the squeling bearings pointed me in the right direction.
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