foglights, tapping into low beam

[Joep3d]

Hello, I have just purchased an aftermarket fog light system, I am prewired for the foglights but I do not have the correct stalk or combination switch for fog lights and instead of paying 125-150$ for the part id rather just tap into my low beams to my headlights, I know how to wire the fog lights and what not but I cannot figure out the wire I should tap into is just the red wire going to the lowbeam bulb or what, is there any problem with this meathod as it seems to cheap and easy to be true... I will be using a relay with a 20amp fuse to the battery.