I have a GMP 100 furncace that I replaced the controller card this winter. At the time I did hook up the air conditioner. I have misplaced the installation instruction.

The thermostat has 4 wires y g r w

How do I connect the condenser to the thermostat?

I not sure where to connect the second wire from the ac contact

I think you are wanting to connect the tstat wires from the furace and runs to the condenser unit, am I correct (don`t know exactly what you are calling a controler card)
If I`m understanding right you tie one wire to the yellow and the other wire to common