I updated my annunciator panel with my panel upgrade/AP and it was a learning process to try to understand how these were built and how Mooney wired them.  I learned a lot in the process (as did my install shop and IAI) and thought that I'd share in case anyone needs this for reference. First off, International Avionics Inc. made the annunciator panels and many voltage regulators for Mooney.  However when they built an annunciator they had several indications that had common location in the