One Leg Ballast Resistor or Two

Don't go by wire colors, unless you can post the diagram it refers to

But look at the 4 pin ballast in the diagram I posted. NOTICE the notch in one end? This is IMPORTANT. It places the ballast in the proper orientation, because the two resistors inside the 4 pin ballast are DIFFERENT from each other. Therefore if you turn the ballast around in the diagram the incorrect resistances be in the circuit.

Notice that in reality, all you are doing with the 4 pin ballast is adding one more wire to the ECU