I am putting some aftermarket fog lights on this weekend and would like to wire them in to my factory switch to come on either with the parklights or the headlights and stay on with the highbeams. how would I go about doing this?? I have a wiring box with test light ect.

 

I would use a relay, like this one:

http://www.dieselmanor.com/electrical/relay40A.asp

30 terminal to the positive battery terminal, via a 20-30amp fuse
87 terminal to the fog lights
85 terminal to chassis ground
86 terminal to your parking lights, via your fog light switch

If you wire it this way, your fog lights will be on only with the parking lights, or the headlights on either beam, and provided the fog light switch is on. So in order for your fog lights to go on, at least your parking lights must be on, and your fog light switch must be on. I assume you already have an existing fog light switch, if so then you just have to unplug the factory harness and splice into it from the 86 terminal of the relay. This is pretty basic wiring, but if a schematic would help, let me know. Good luck.

 

I agree, Do it with the parking light circut so they are always on. You can run an auxillary switch to turn them off if you want or just run it directly through your parking lights. I am doing the same thing but I need to figure out how to disable my daytime running lights. So I am in the middle of this project as well.