I just replaced my air conditioner / heater with a used air conditioner. On my old unit, there were four wires connected. Red, Orange, Blue and Green. On the new unit, there are only two places, that I can see to attach the wires. I attached the Red and Yellow wires. Here is the problem; When I have the thermostat set to off, fan to auto, the blower works, as it probably should. When I have the thermostat set to cool, the compressor kicks on, and starts to cool the coils, and the fan kicks on, but the blower shuts off.

Can anyone tell me what's wrong?