16. Once all of the outputs/loads have been connected, the Mastercell input harness can be connected to the Mastercell and the inputs/switches connected. As we mentioned in our opening text, all switches now make a ground connection. For instance, your typical standard brake light switch would have power going to it, and when the switch is closed (you step on the brake pedal), it completes the circuit and feeds that power all the way to the rear of the car to the brake lights. Shown here is how the ISIS system now handles brake lights. The yellow/orange and yellow/green wires come from the Mastercell and the opposite side of the switch is grounded. When you apply the brakes, the two yellow wires are grounded, telling the Mastercell what to do. The reason there are two wires on the brake light switch is because one controls the regular brake lights and the other is for the CHMSL in our decklid.