Radar not working

I have several planes with a radar on the panel eg. F16 Viper
that allows you to point to the radar contact and display its details - It did work in FS2002 but it wont work in FS 2004
Can some one explain what i have done wrong
that allows you to point to the radar contact and display its details - It did work in FS2002 but it wont work in FS 2004
Can some one explain what i have done wrong