I love GM techs. They are "the man". They know more about our rigs then we do. They also have the best training. Plus most of them are cool guys and will even answer questions on the phone if you have half a clue about what your asking.

 

HUH! I found my today. It's on the drivers side under the hood. There is a quarter size plastic bolt that you unscrew and the whole cover comes off. The horn relay will be right in front of you when facing the side of the engine. It also has a 10 ampfuse next to it, to your left. In CA at Auto Zone I bought them for $12.99 + tax. The one directly behind it is for the A/C and italso has a 15 amp fuse next to it. My A/Cis blowing hot air and my horn doesn't work either. Upon replacing both relays and fuses, I still have nothing.
GOOD LUCK!