Having a problem where EFIS mode of the autopilot is not behaving as expected. The AF-Pilot works in "standalone" mode, i.e. it will follow a track and do climbs and descents when commanded. The AP will also enter EFIS mode after pressing the EFIS button, and the display says "EXT LS VS". To me this implies that the AP is receiving valid ARINC data. However, the autopilot seems to only ever command zero bank and zero pitch in this mode. Changing the heading bug has no effect, even though the EFIS is set to HDG for lateral control. Same with altitude bug.

Here are some items I've noticed that seem suspicious. Are they related? The flight director is displayed, but it always follows the airplane wings, regardless of how the AP is configured in the EFIS. I would expect that the FD would move around even when the AP is completely disconnected. Is that incorrect? The AP mode display at the top center of the EFIS display also has a red X over it. The FD also seems to have a red outline, which does not exactly match the pictures in the User Manual. Is that indicative of a problem?

The RS-232 input to the AP is not connected from the EFIS, rather it is connected to the output of the 430W. Is the RS-232 input required to be connected to the EFIS in order for GPS steering to work? The installation documents imply that it should work in this configuration.

Thanks for any information you can provide