The PCM failed in my 2014 Silverado 1500. I purchased a programmed to my vin PCM unit from the internet, but I'm struggling to get the key to program after replacement, as it will not start. The security light is not on, and all the instructions I'm finding on the internet show to turn the key on for 10 minutes until the security light goes out, then cycle the key and leave it on again for 10 minutes, repeat this process 3 times, and the key will reprogram to the vehicle. I can put the old PCM back in, and it starts right up. Do I have to take it to a dealer to get programmed? Any input would be appreciated.