The controller will need to be scanned to find the fault. The light that is blinking is much like the "engine" light that comes on when something is wrong in the system. Being that there are so many possibilites, it is very difficult for me to know which component is at fault here, but most major transmission shops will run a scan for free and be able to give you an estimate on what it will take. About all that you can do is to check all the fuses, with a fuse tester, as there are a few electrical components that are fused in.
If you have further questions on this, please feel free to reply.
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