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the factory switch only sends a ground to the factory relay, the switch does not have the power for the lights going through it. so YES its fine, but you will need to use 100W relays for the lights, since the factory fogs are 55w each.
just last week I installed aftermarket fog lights using the factory switch and relay, I found all the wiring info I needed on this site, even the instructions for making them work with the parking lamps, low and high beams, it was super easy. Just try a search, bit dont count on the factory relay to handle 200 watts