17. Wiring the unit is pretty straightforward. Every application is a little different, so make sure to follow the detail instructions. The main power wire must be attached to the positive battery post. Also the ground wire should run to the negative side of the battery, but a good chassis ground will work. There are only eight wires you need to worry about to get the system running. Options include: timing control, cooling fan control, A/C kick up control, and we used them all except the timing control.