The alarm goes off whenever I open the passenger door or pop the hood, not sure why.

So what would happened if I pulled the horn fuse.

'03 G35 coupe.

 

More then likely, your horn would not honk...

 

The horn won't work

 

Pull it and see.. Nothing major aside from your horn not working. I don't have a schematic to see if anything else ties in so for me it would be trial and error.

 

I had a car that had the horn and cigarette lighter on the same circuit. You can usually find out from the fuse block cover(s).

You should really figure out why it's doing that first, instead of band-aiding. But if I were you, maybe I'd do the same . It's hot as ***** oustide in TN and trouble shooting in this heat would suck.