Check out the latest video where we install factory fog lights on a 1999 jeep cherokee xj that did not have them from the factory. You will see that Jeep installed wiring for the switch illumination so the other 2 wires are used for power to the relay and switch. The 4 wires on the switch are:
Black is ground
Purple is for the 12V run source for the switch - from the fuse panel.
Blue will be the 12 volt out to the relay
Orange is the illumination for the switch.
Not the on light but the fog light symbol when you turn on the headlights.
The black and orange are hooked up and have power and ground. When I plug in the Factory switch and turn on the headlights the symbol lights up. There is no power to the blue or purple wires prior to this install.
Wire loom: Alex Tech 10ft - 1/2 inch Cord Protector Wire Loom Tubing Cable Sleeve Split Sleeving for USB Charger Cable Power Cord Audio Video Cable - Protect Cat from Chewing Cords - Black https://www.amazon.com/dp/B07FW3GTXB/ref=cm_sw_r_cp_api_i_pddIDbEA2D0SK
Fuse taps: 10 Pack - EPAuto 12V Car Add-a-circuit Fuse TAP Adapter Mini ATM APM Blade Fuse Holder https://www.amazon.com/dp/B01DYQM6EO/ref=cm_sw_r_cp_api_i_3edIDbJCN81TV
Relays: Nilight 50003R Automotive Set... https://www.amazon.com/dp/B0748F1JK4?ref=ppx_pop_mob_ap_share
Lights: Driver and Passenger Fog Lights Lamps Replacement for Jeep SUV 55055275AB 55055274AB AutoAndArt https://www.amazon.com/dp/B008G317MI/ref=cm_sw_r_cp_api_i_zgdIDbZXQ246J
Jeep fog lights install Cherokee XJ