2012 Buick Enclave will not start
Replaced battery Summer 2017. December 2017, drove to CVS and parked and when I returned I turned the key and nothing. Tow truck driver tried to jump it and nothing happened. Had it towed to dealership where it stayed overnight. Vehicle started for dealership, they could not duplicate the issue. No issues until November 2018, noticed security light (vehicle with padlock light on dash) was on. After turning the car off, car would not start. Had it towed to dealership, after 2 weeks they replaced the fuse box ($600+). Dealership also stated that the starter "may" be going bad and they could replace for another $500. Opted out of having start replaced. Two weeks later the same exact symptoms (i.e., security light came on when it turned on and after driving and turning the car off it would not start). Had vehicle towed to local mechanic. I let them know that the dealership had replaced the fuse box and they asked why. I explained the above symptoms. They checked a purple wire under the hood and stated that power is getting to the starter but that the starter isn't engaging. They replaced the starter ($600+). January 2019, same issues..security light on, etc...I have tried remote start and using different keys. Went through procedures for resetting security system, leaving door open and pressing the lock button on remote, turning the key to ON position w/o starting and leaving for 10mins. Security light stayed on. Repeated the process 3X and still nothing. I checked battery for sufficient cranking volts (13.9v) at battery terminals. All interior lights, signals, radio and electronics operate as expected. Anyone have any ideas?