99 Sierra, fog lights

any one know how to have the fog lights come on automaticly when you start the vehicle, instead of having to push the button every time.

Doesn't your Sierra have daytime running lights? If so, why not tie a relay to the headlight wire to put 12V on the fog lights?? Drive the coil with the Daytime lights, feed the contact with 12V, and the other side to the fog lights. Maybe I'm missing the point, do you mean all of the time (which doesn't sound right to me). If you have Daytime Running lights, the parking lights aren't on with them, tie the relay into the parking light system. BUT.....I'm not sure where you are located, but here in PA the inspection laws would keep you from doing either of the above without a switch to turn them off.HotRod