Did you try running the diagnostic test to see if unit is showing gps connected? Manual has instructions for how to do this.
The Accessory Test View shows if it is connected.
The GPS Diagnostic View shows its performance.
Humminbird Helix 12 CHIRP SI, 1198c SI, 1198c SI, ONIX 10 SI NT, Helix 7 CHIRP SI GPS G2, 360, RC-1