We've been having an intermittent problem with selecting the EFIS function. Push the button and every now and then it just stays in AP mode.

It finally solidified today into no effect what-so-ever when you push EFIS. It just stays in AP, which works normally.

It doesn't matter if I select EFIS or GPS for the input. Still no effect.

Has anyone else seen this? I'm not sure if I should try troubleshooting wiring or if there's another test I can do.

Dave