Thanks! No EMS. It's a D-10A and the autopilot with AP74, and connected to a GPS.
I get a heading indication, but didn't think to note whether that's coming from the remote compass, or the internal one. I'm not sure how to check that. Is it indicated in DSAB Setup, or some such place? I haven't noticed any error message about heading or remote compass.
The wiring doesn't appear to be broken or frayed, but I haven't looked hard at it yet.
Is there any way to check the integrity of the OAT sensor--a resistance reading, or something like that?
I don't find the error message that I see ("PRIMARY OAT SENSOR LOST") in the D-10A installation guide, but there is "OAT SENSOR NOT DETECTED This alert appears when the EFIS has an OAT connected and then loses that connection for some reason. Either the EDC-D10A has become disconnected, or the OAT sensor itself has become disconnected from the EDC-D10A." Is that the same thing, just worded differently, or is it a different error?
Does "SENSOR LOST" mean that the sensor is detected at first, but then later lost? Or not detected at all?