There is a .8 lt green wire that comes from the AC selector and would be in the passenger side heater/AC harness. It goes to the pressure cycling switch that is screwed into the accumulator/receiver/drier. It may or may not also have a .8 lt green pigtail on it, that is for a solenoid that bumps up the idle speed when the AC is selected. The other wire off the cycling switch is .8 dk green and goes to your compressor clutch connector. It may or may not also have a .8 dk green wire that goes to the computer. The other wire off that connector is a .8 black and it is a ground. On computer cars, the computer raises the idle speed to compensate for the compressor, but on non-computer cars, you need a solenoid that bolts to the side of the carb and it holds the idle linkage open a bit instead.