Did a flight and when I tried to set the coarse I clicked on the Nav Source button and it did nothing. Could not switch from GPS to NAV1. After a while it did change. Also when I did an ILS approach, and switched over from GPS to NAV1 the plane didn’t follow the approach. I was close to final, activated APP, went from GPS to NAV1, correct ILS freq was entered, Coarse was set and plane did not follow approach. Anyone else have this problem? Or any suggestions on why this is happening? Seems like I did everything right and everything was set. Thanks, Walt