If you are not getting a blue LED flash then the NMEA input isn’t correct into the QK-A031. You could try to reverse the “+” and “-” of the DSC input.
What wires are you connecting for this connection? It sounds like the DSC information isn’t getting into the QK-A031. You will see the LED light up once a valid NMEA signal is received.
Please let me know about the colour of the connections and how it’s set up? I
Im sure we can go from there and get this sorted
Best regards