Nav/GPS switch works for me and it tracks flight plan very well in GPS mode, but i Nav mode, it's either I am doing something wrong or it's not working properly.
I tried to have a flight with VOR routes only, just to keep my self more busy during flight, tuning frequencies and adjusting other things. Flight plan made with default P3D V4.5 flight planer. For that task it's ok.
So I tune my Nav1 frequency to VOR I am flying to and adjust the course as required. But plane struggles to capture the course properly. It is doing quite steep turns to capture the course, than overshoots it and tries to capture from other side and that is happening when I am still quite far away fro the VOR, lets say around 100 miles or more. Shouldn't it be more gentle when capturing VOR course from longer distances? Or I should fly in heading mode, to get closer to the course and only then capture it?  Would really like to understand it better, cause I find it much more interesting to navigate this airplane in Nav mode by VORs. I guess it is how it was really flown in the past.