'07 Tahoe horn problem

[Mrfix71]

I recently bought a beautiful 2007 Tahoe LT 4x4. After a test drive and verifying the important stuff, I got it home and was playing with some of the many luxury features. During all the doodling, I noticed that the horn did not work. I replaced the blown 15a fuse but the horn still did not work, either by pressing the remote lock buttons or by pressing the steering button. I tried to Google some answers, but didn’t find anything on horn or horn relay locations.
A day or so later I was again reading the owners manual and when I locked the doors with the key fob, the horn sounded. I locked and unlocked the doors and noticed that the horn would sound when I pressed the lock button twice. However, the horn sounded significantly weaker compared to my last vehicle. Today, the horn does not work again.
I have the wiring diagram, but do not know where the apparent TWO horns are nor where the horn relay is. Does anyone have any valuable input?

 

[ScubaJim]

I have a 2008 and one of the two horns in mine failed as well sounded pretty week had to replace it. It was under quite a bit of pluming. Works fine now. (sounds hearty) I would pull the horns and check them.

 

[Mrfix71]

It seems like just changing out the horns will more of a chore than any other I have done before.
I looked a while back for a guide on working on the horns without much success. is there a guide or something out there?