I'm working on the NAV in the dashboard, which is already difficult enough, and my arm keeps on bumping into the super sensitive horn on the steering wheel. Makes me jump and I'm sure my neighbor hates me now. Is it possible to temporarily disable the horn? I'm thinking of yanking the fuse, but have no idea which one to pull. The diagram is not helpful.

 

I would try this one:

 

If you're not handy with fuses just take the battery cable off.

 

Agree - best to unplug the battery when working on this type of stuff, especially involving the nav.