Frost, I thought about using the existing horn circuit but I've always been disappointed with the lag time between pressing the steering wheel and waiting for the horn to honk. Maybe that's better in the newer models but my 14 is bad.
The stock horn can be accessed on my truck by opening a trap door in the top of the driver's side front wheel well. I found that after spending an hour trying to get to the horn from the top, under the battery. LOL! ~Jeff