Horn doesn't work

[Jeff Froehlich]

Hi all, I have a 2017 GMC 3500 Sierra.  About a month or so I noticed my horn would blow when I hit the lock button twice on key fob.  Didnt think much of it, figured it was my remote.  Then the other day I went to blow my horn and it didnt work.  I have checked the settings and it is set to sound horn, checked fuse and checked relay.  All were good.  Anyone have any other ideas.  I know there are two horns and find it odd that they would both go at the same time.

[Ponyboy6]

Same issue with mine 2016 Duramax 3500. Believe it's the relay.  But I can't seem to find it. Truck manual doesn't show horn relay.

[Swandog66]

I have A 2016 3500 duramax and have The same horn issue. I read in a search the horns can get water in them causing a failure. I was just under my truck and if I tap the horn and double tap the lock button on the key fob the horn blows a couple of times then quits .I just ordered the last horn on R.A. Leading me to believe it must be a common problem . The horn is straight in front of driver wheel on the corner of the radiator support looks like I will be removing the inner fender to replace the horn. Also thinking of relocating the horns to the inside of the fender next to the battery to keep them dry. 

[Swandog66]

Horn location. 

[Jeff Froehlich]

I will try tapping the horn and see if it works.  I also will add that when I had said I checked the relay, I did so by activating horn and I could hear it clicking.  Upon further checking I decided to actually try a different relay.  Well, there is none.  Since it wasn't labeled, I pulled every relay one at a time and had my son hit the horn each time.  Each time I could still hear what I thought was the relay clicking.  I read somewhere that it is some kind of board inside the fuse panel in place of the relay for the horn.

[Swandog66]

I did the same thing I could hear it clicking and couldn’t find it. I believe you are correct about the hidden relay. 

[Jeff Froehlich]

I tore into it today.  You would think they could put the horn in a better spot that is a little easier to access.  Had the horns out and tested them and they worked.  Put them back and nothing.  Fiddled with plug and they work.  I'm guessing either the plug on end of wire or horn may be the culprit.  As of now it works.  

[Swandog66]

As I said I ordered new ones and I’m still thinking of relocating them up into the fender. As you said there not very accessible. And I always put dielectric grease on any connection I take apart.