If you've ID'ed your system correctly here this model uses a blade type SSD. There is no cable connection as the SSD is plugged directly into the logic board via a connector.
Here's the IFIXIT guide for replacing the SSD: [guide|12823|MacBook Pro 13" Retina Display Late 2012 SSD Replacement].
I would pop the bottom cover off and do a good inspection looking for signs of liquid damage here.