The Ford "blue grommit" module is the most common of the early elctronic Ford modules. It has two plugs coming off of it. One plug has two wires, red & white. The other plug has four wires, purple, orange, green, & black.
Wiring is as follows
Red - 12 volts when ignition is on
White - 12 volts when cranking
Purple & orange to Hall Effect Sensor in distribitor, factory Ford
has like colored wires off distribitor
Green - Neg side (Tach Side) of coil
Black - Ground, but also hooks into distribitor in factory wiring
The white wire retards ignition timing when starting, it also hooks to Pos side of coil to deliver 12 V, when running coil only gets 6 V
The white wire can be left unhooked without causing any problems, unless your initail timing is set very high. I've been told it can also be used to retard timing for nitrious, but have no idea how well it would work.