There are three wires that need to be connected to your headlight switch. One wire powers the headlights for the automatic lights, one wire is used for the "headlights on" warning chime, and the third is used for the dome light circuit, which must be modified. There are two wires on the Ford headlight switch that require mods as well, if you wish to have the theater dimming/delay and the dome light work from the headlight switch. This is well documented in the Painless module's detailed instruction manual. Since the Ford headlight switch turns off the front parking lights when fully extended, make sure you connect the Painless module's brown wire to the rear taillight circuit, which is the R terminal on the switch (remove the connector to see the letters on the switch body).