Grom BT3 sat nav not displaying

[SparkyZ4]

Hi all

Fitted the Grom BT3 this evening, spent 30 mins trying to find the coaxial cable, nought fitted at either the CD changer or on the Carver DSP, went ahead and fitted the BT3 anyway

All works, save I am unable to access the Sat Nav now.... if I play the radio or through the aux (aftermarket add on) I get the sat nav, if I set the sat nav then go to cdc I get voice just no map.....

Help any ideas anyone?

Thanks in advance a confused Sparky