Code 3 WingMan for Crown Victoria - Manual (Page 7)

7
It is advisable to leave an extra loop of cable when installing the lightbar to allow for future changes or reinstallations. Connect the black lead to a solid frame ground (earth), preferably the (-) or ground (earth) side of the battery, and the remaining power wires to the +12V terminal of the battery, power switches, siren or RLS controller. Each lighthead is wired independently to allow complete flexibility of control.
Wiring Diagram
Wiring Instructions