Added a second horn because Mazda didn't

I don't use the horn often, but when I do I want to make damned sure the intended target hears it.
In order to save probably $3.39 per car Mazda goes with a wimpy single horn, so I took inspiration from this thread and installed a second:
http://www.mazdas247.com/forum/show...n-Upgrade-Multiple-Pics-56k-connection-beware

Luckily on the 2012 M5 there is absolutely no need to remove the front bumper to get plenty of access to the horn area. In fact there's enough room in there to add a several bugle-type air horns that play la cucaracha if you're so inclined.
Note: this would also be a good time to install fog lights if you've got a sport model like mine. There's a plug running right there and everything, with the other end behind one of the blank dash buttons I assume.
I haven't decided if it's worth it or not to put them in. We have a decent number of foggy days here in Milwaukee, but honestly in my other cars with FL's they don't seem to do much to help visibility, more of an appearance thing IMO.

Back to the beeper. I chose this "low" tone horn: https://www.amazon.com/dp/ (commissions earned)
2 day shipping was free with Amazon prime, maybe you can get a better price locally if you don't have "Prime" and must pay shipping.
BTW I also bought this tire pressure gauge, very nicely made and gave the exact same reading as a $150 oil-filled gauge at a friend's garage.
https://www.amazon.com/dp/ (commissions earned)

Anyway, I jacked up the front end, removed both front tires, removed the engine undertray via numerous 12mm bolts and annoying little plastic pop-clips (there's surely a removal tool that makes this a piece of cake, or you can use a flat blade screwdriver and pair of pliers, and a dozen or so choice curse words), and finally more plastic pop-rivets in driver's side front fender liner. No need to take this liner completely off, just enough clips to allow peeling it back back out of the way. Don't need to touch the passenger liner.

Enlarge one of the mounting holes in the bracket that came with the new horn with a 3/8ish drill bit and use the same chassis bolt as the OEM horn bracket to mount. After fiddling with the position settled on the new horn almost directly above the exisiting, with the horn facing down like the other.
Solder the power lead (you supply the wire and female connector) from the new horn into the OEM horn's single-wire lead after stripping off about 1.5" of protective wrap and ~1/4" of insulation from the wire, wrap in electrical tape and then heat-shrink and voila, at least double the hp (horn power).
With the fender liner and undertray there really isn't any kind of clear path for the sound waves to get outside at whatever jerk you're beeping at, but I can confirm that standing anywhere in front of the car when it's blaring will not be missed. Plus it imparts a nice buzz to the driver's feet

Took me about 1.5 hours start to finish which included drinking a beer and BSing with my father, who's in town visiting.

(breakn)

sorry for the dark pictures

Secured on jackstands:



Single horn:



double the fun:

Quick question: where'd you place the jackstands?

quick answer: under the front suspension pick-up points.

Well done! Having the upgraded horns definitely improves safety, and certainly gets even the most distracted of idiots attention. Seeing the space available there on the Mz5, I'll have to follow your lead. Nice job.

I had installed these on my Jetta:
https://www.amazon.com/dp/ (commissions earned)

thanks Fitz - oooooh I've always coveted those Hellas. No issues with water hitting them?

The black plastic pieces around the M5's fog light area are easy to pop out, while under there I was thinking about cutting out some sections to let the sound out but wondered about water getting in.

I put this Wolo air horn in the Jeep that got replaced by the M5. Man that thing sounded GREAT, only thing was when locking the doors the signal was so short instead of a short "beep!" you got a short "pfffft!" from the air compressor
https://www.amazon.com/dp/ (commissions earned)

I have a 2012 Sport and I was able to add a FIAMM low note horn to the existing horn just by accessing it through the engine bay. Behind the headlamps, there is room for an arm to reach in and remove the single bolt holding the horn bracket. The bracket has a hook so it won't fall to the undercarriage panel. Simply pull the bracket and horn up to where you can release the wire harness with your other hand.

I have 2014 GT. I had to use the jack that came with the car, and turned the wheels all the way to the right. I never got underneath the car so that worked out alright.
I own jack stands and a hydraulic jack but with the low clearance of the body I was not able to figure out where to use the hydraulic jack so I could get the jackstands under the jacking points. Thats something I will spend more time and figure out later.
I took 5 clips out of the left wheel well from the front working my way up and was able to pull the plastic back. I then took off the 4 screws from the plastic underbody directly in front of the left wheel. This was enough to allow all the plastic to move out of the way and I could now see and reach the horn. I unplugged the single horn harness wire and unbolted and removed the horn and the post it is attached to and brought it out. I found that the stock horn is a High Tone FIAMM Freeway Blaster. I had already bought a Low Tone FIAMM Freeway Blaster. The FIAMM horns draw 6Amps each, so adding 2 should not tax the 15 Amp stock horn circuit.
Next I built the simple harness using 1 male and 2 female connectors and 14 guage wire, as described in this other post (http://www.mazdas247.com/forum/showthread.php?123758681-2007-Mazda5-Horn-Upgrade-Multiple-Pics-56k-connection-beware).
Then I installed the second Low Tone horn using its supplied post onto the stock horn's post using the bolt that connects to the body work. It was a little tight reaching in, but with some help from the wife who has smaller hands I was able to get it all bolted tight.
The horns worked fine, and the 2 tone combination is a lot louder.
Thanks to everyone who has posted on this topic earlier.

I was not able to reach from the top - I could feel the bolt, just barely, but could not see it. I felt reaching from the top I would end up breaking some of the wires that are in the way while doing the work. Seemed too risky, at least to me.

Or you can do it the easy way and simply upgrade to a GT (factory alarm, at least on the <'10 uses the horn as siren -didn’t say it was cheap)! The horn is pretty standard. You can swap in just about most any OE horn. Pull one from a full size car/truck and add it on for more volume on the cheap.


And the front bumper comes off really easy to make life easier but you do have to pop a few fasteners and a bunch of screws/bolts.

^^^^+1

Yeah it is a LOT easier to pull the bumper. 10 screws at the bottom lip, 4 on top, 3 plastic fastener on both side to peel off the fender liner partially and 1 each side to unlock the bumper. A LOT easier working on the horn squatting/sitting than on your back. Bumper is off in 5-10 min. Its so easy my 16 yr old does it all the time.

I had those Hellas on a Hyundai cursed with a cheap horn and I loved them. But I love my air horns on the Mazda much more.