You know you have a fully diagnostic top. If I as you I would strongly consider going to a shop that can diagnosis this. Not just any shop but one that has this capability. Or if you know someone with Carsoft v 8.2 or newer they can dot for you too.
Your light blinking is a good sign because you have power to the switch at least. Once the problem is idenified you can work to correct it.
Most mechanics can't do top work unless they have some good OBDII scan tools.