This is important to fix since I can't pass inspection without a horn, my horn stopped working a while ago, I know its not the horn since I bypassed the relays to test it, where is a good place to test, I know of 2 relays, 1 in the BEC, and the other mounted above the radiator. Also, when pushing the horn button, a one time click would be heard from the relay in the BEC.

 

Horns, plural.
There are two.
Any voltage at the horn terminal when the horn button is pressed?
Is fuse 46 blown?
The grounds would be the next place.
They are next to the hood support rod hinge.

 

Fuse 46 is fine, I attached a few pictures of how this is wired, this is an aftermarket horn so there is only one horn, the relay that I circled in the BEC will repeatedly click if I hit the key fob for the trunk unlock or the panic button. The power for the horn runs to the relay mounted up by the radiator cover and there is a photo of that as well.

 

Sorry, I cannot support aftermarket wiring.
I dont know what they did, but an aftermarket
horn does not require a new relay.
I added TWO aftermarket horns to the TWO
OEM horns and no extra relay was needed.
It looks as someone has jerry rigged your
aftermarket horn for no reason at all.
I even have one mounted in the trunk area
for those drivers behind me...

Ahhhh Ooooog Gaaaah

Go to wally world and buy a canned air horn for a boat.
That will get you thru inspection.
Just blow it when he presses on your horn button.

 

if you can get it to work without all the relays and stuff run a momentary switch into the cab with 12v power and make it work that way...

other than that trace out all the wires making sure power is going into relay, your switch is sending power to the relay and if power is leaviong the relay when pressed why is horn not working, bad ground to horn...

 

Yea, a friend and a $4.99 test light works
wonder when trying to see electrons flowing
with the naked eye...