So was given a free pair of auxiliary fog lights for my truck from a buddy. they are very similar to these if not these exact lights.

I also have a wiring harness for the fog lights i want to install, and the diagram for the wires goes as shown below. the switch that goes inside the cab lights up when in the on position only, is there a way i can make it so it illuminates every time the vehicle is started or the headlights are on? So the switch illuminates so i can see it at night even when the fog lights arent on.

 

Year, model, trim level?
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Yes, but you need to find the internal wiring diagram for the switch. If you can't find it, you'll have to do some testing on the switch so we can figure out its internal wiring.

 

1999 F150 XLT 4X4 5.5L V8 Triton

 

If it has a separate wire for switch illumination you can tap into the light blue wire/red stripe behind the dash dimmer switch. I'm thinking that even with that it'll only be illuminated when the switch is turned on and the lights are on, don't know if the switch has internal circuitry for the light. Probably does. You may have to use a different switch for what you want.
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