goodman furnace /ac no y terminal on board
The furnace doesn't need a Y terminal, and in a lot of cases when it does have one, it's not connected to anything in the furnace.  Connect the wires from the thermostat as follows:


Red connects to R in furnace and R on thermostat.
White connects to W in furnace and W on thermostat.
Green connects to G in furnace and G on thermostat.
Yellow connects to the Red wire to the condensing unit.
White wire from condensing unit connects to 24V common terminal of the transformer.




Notes:  


The 24V common terminal of the transformer should be grounded to the chassis, as well as connected to PIN 6 of the Molex connector on the board.
*The "hot" 24V terminal of the transformer should be connected to PIN 3 of the Molex connector on the board.