horn is not going to make a ses light come on, take it to autozone and have it scanned.
the horn, look under the hood, find the horn, (its up front by the grills) check the wires to it, if you run 2 wires off the battery to it, it should beep, if not buy new horn, they are cheap. and you can pick the tone you want too. deep or high pitched, or in the middle.
@GTLGDP, what is the year of your vehicle?
Michelle, GM Customer Service
Its a 2000 GTP. Also, how much would it cost to get a spare key? (Mine has a chip in it)
yeah i believe the instructions on that site i gave him tells you to use the original key, take it out and then put the new one in to program it.