I purchased a used 2015 GMC Terrain. It does not have factory navigation. After a little research, came across a site selling a nav unit off a 2015 GMC Terrain Denali. I purchased the bezel, radio and monitor. I was under the impression that once installed and added the nav antenna, the dealer could program to my vin to activate. Took to dealer with original vin of equipment including the radio id and the dealer refused to reprogram it. Said it was more complicated than that. As of now, the radio screen just shows “Locked.” Any ideas? Have no problem removing and reinstalling mine if it can’t be done.