Skyview to D-180 help

I'm trying to get the gps info from a Skyview to a D-180 so the D-180 can calculate and display the winds aloft. I am using serial port 4 to transmit the info from Skyview. I have connected the blue with orange stripe (TX) wire from Skyview to the input wire of D-180 which was existing from and successfully used with the EKP-IV that has since been removed. Serial port 4 settings are:
NMEA OUT - Full
Serial in/out rate - 4800

The D-180 is computing winds and displaying them but they don't agree with either the direction and speed that the Skyview is displaying. I am confident that the Skyview is the accurate one.

Any ideas?

Thanks

Wind direction and speed calculations require accurate magnetic heading info.

If the mag inclination and calibration haven't been done for the D-180 it would be unable to do a valid computation.