goodman furnace /ac no y terminal on board (revisited)
Use a relay

You can wire a standard HVAC "blower relay" of the SPST-N/O type with its coil connected between Y and C  and its contact connected between G and R and mount it in the furnace's wiring compartment.  This allows the thermostat to energize G by itself to turn on the blower without energizing Y by accident, but also energizes G to turn the fan on when the thermostat applies power to Y to call for compressor.