The hood signal lights connect into the main wiring harness that runs from the firewall to the headlights/parking/turn signals in front. There is a pig tail socket that is factory made. If you have a Mach1 the pig tail is located along side the drivers side hood hinge. It meets the main harness in that area. If you have a car that never had the hood signal option,then you will be splicing into the factory harness. You should get a Haines manual and check the schematic to find the correct wires.