The exciter patch as mentioned above goes through the instrument panel. One of my previous 951's had this issue, it drove me crazy. I finally found that the circuit was broken in the ribbon cable on the Instrument panel. Soldiered a bypass wire and all was good. Took hours to locate it, but once I pulled the manual, it was fairly easy to track down. Hope this helps.

 

A while back for custom builds and also mairine installations with similar issues I made modules to solve this problem .. see details of the module here - http://www.igniteautomation.com/docs/exciteme.pdf