The electronic compass is part of the VesselView system. I believe the compass it is part of the SmartCraft antenna (mounted on the starboard side of the hardtop), but not certain.
There is a page under settings on the MFD and a similar one on the VesselView where you can see the sources of all NMEA 2000 data. You need the ignition on for VV to be active, then look for heading data on that screen, though if your question is cos its not working then that isnt going to help....
I will look next time I am at the boat.
