John, there is a red light on the ADAHRS that can give you some information. It's documented in the Installation Manual Section 21:
For modules such as the SV-ADAHRS-200/201, the SV-EMS-220/221, and SV-ARINC-429,
observe the red LED light near the SkyView Network connector:
o Flashing Fast: The module is operating normally and is configured and communicating on a SkyView Network.
o Flashing Slowly: The module is operating normally, but is not active on SkyView Network.
o Off: The module is not receiving power (from a SkyView Network / Display)
o On Solid - the module is receiving power, but is not operating normally.
Check what the red light is doing, and then if needed contact our tech support people and have them troubleshoot with you.