07 Milan AC Line Freezes When Driving
 

AC line freezes with AC on and defroster on (even with AC button not engaged), no matter hot or cold setting, but only when driving and not when idle.
Replaced low pressure switch; compressor was tested and is good. No leaks. New freon. Line still freezes.
Anyone experience this and know what needs to be fixed or replaced?
https://cimg8.ibsrv.net/gimg/www.mer...8a3de421b2.jpg
Frozen AC line