Fitting Horn all done at your own risk.
Good news I’ve fitted my horns. Two new ones and the original. Much improved could be better.
Tools needed small screwdriver to pop plastic clips, Philips no2 bit screwdriver for rubber stops.
12mm ratchet screwdriver for horn bolt. 10mm spanner/socket for screwing new horns down. Two M6 nut and bolts for the extension brackets, two M6 bolts for horns to cross member which is already tapped for you. Four washers to suit. Crimp tool or solder for the spade terminals. A magnet on a stick would come in useful too, one of those bolt fishing ones! I would advise using a little grease on all nuts, bolts and paintwork areas that touch. Some sleeving to go over new wires to protect from chafing.
There are two options here, keeping the original horn with the new ones, or dispense with the original and just use your new ones. I used Low Note FIAMM AM80SX the AM80 is slightly bigger they should both fit, need a wiggle., and PIAA all their models should fit again with a wiggle. I also kept the original horn. Fine with a nice accompaniment.
The theory that I could connect to the original horn worked. Using a scotch block didn’t, not enough cable to connect to, much easier to just extend the horn plug to horn and add looped wire to your new horns.
I tried fitting the FIAMM horn into the gap by the bonnet catch, passengers side and found the Low note fitted there. On drivers side the high note horn was too big but the PIAA fitted. So I ended up with PIAA and FIAMM low note horns. The brackets needed an extension about 90mm with an S bend, see photos, I made these out of a strip of mild steel, bends easily in the vice, bit of trial and error. Make up a wire harness similar to the photos, all shrouded spades. Male spade to horn plug, female spade to original horn with wire loop to new horns, female spade wire loop to second horn. Male spades on each horn bolted to bracket for the earth (-ve)
Before work pull the HORN fuse Passenger side box 7.5A brown, try the horn push to make sure you have the right one there are two. The horn cct is still live with the ignition off. Note where the fuse lives.
I removed the large plastic shroud that fits around the bonnet catch, five plastic pins (one below) removed and the two rubberish stops unscrewed, Philips bit, do not use a Pozidrive it’ll chew it up! NOTE the plastic lugs at the front fit back under the metal lip where the rubber seal is, see photo 4. Another plastic shroud fits below the bonnet lock, on the far right, passenger side, remove the one plastic clip, pull up the edge and wedge with a suitable block, this will show you the nut holding the horn. Now there is little room working here and best to sling some wire around the horn to stop it dropping when you remove the bolt. And to stop the bolt dropping some thin wire round that once you have exposed enough thread. A 12mm ratchet spanner makes easy work on this.
Unscrew the bolt about 6 turns, enough to slip some thin wire round it, give it a twist to keep it on the thread, with some other wire, strongish like car wiring cable, lasso the horn to stop it falling down ( this is where the strong garden wire or similar comes in, to hook it back up when it falls off). Remove the bolt and hopefully it stays attached to the wire you just wrapped round it! This is where the magnet comes in. Now ease the horn up and wiggle it between the plastic shroud and the metal cross member. It will just lift up enough for you to unplug and attach your new wire. Now you should be able to unplug the wire plug from the horn, make sure the plug is well attached to your safety wire, put the horn to one side and plug in your new wire harness, with male 4mm spade terminal attached, a little grease on all the terminals helps here, and possibly a little tape wrapped round the new connections to keep dirt out. You can drop the plug back down with your new wire attached. If your using the old horn as well, plug the other end of your wire harness into the horn, with the extra wire that will go to your new horns. If you not using the original horn dispense with the extra wire.
Now for the fun part, put your bolt back into the horn bracket and position it back over the bolt hole, use your wire lasso round the horn and the other wire round the bolt to align it. Three hand help here. Screw the bolt back part way and remove your holding wires. Now tighten up.
So you now have an extra wire that will go to the new horns, position the right horn with the new wire harness attached and extend the looped wire across to the left side for the drivers side horn, put the horn into the gap by the bonnet (catch your right) you should have attached the earth wire before hand. Now bolt down 6mm into the hole handily supplied by Toyota. Do the same with the other horn. If you have a meter you can check that you have a good earth (-ve) to the body. Both mine were fine but a serrated locking washer, will cut through any paint making a poor contact. Before reassembly check the horns work! Replace fuse with 15 amp micro fuse blue, (they have plastic between the pins, also called low profile micro ) there are some spare fuses in the fuse box, best to have a replacement.
Facebook video sound Toyota C-HR upgraded horn
Or you can remove the bumper and do it that way, lot of room for all sorts of horns, but be aware that air horns draw at least 15amps, they need a separate relay and wiring to take that load. The Toyota relay is rated at 20 amp but the wiring isn’t.