Capts,
To make FS2Crew iFly 737 work in P3D V3, you need to do this:
1. Re-install the iFly aircraft.
2. Install this update from iFly.
http://ifly.flight1.net/forums/forum_posts.asp?TID=14899&FID=13&PR=3&title=revised-file-updates-26-aug-2016-0300z
3. Run the P3D V3 iFly Config Manager and enable FS2Crew.
4. Manually copy the FS2Crew .gau file from here:
Main P3D Folder\FS2Crew2010\Versions\IFly737\Gauges\
And copy it to the main "Gauges" folder in the P3D V3 directory.
That's it!