Dual Horn Setup (One for Steering Wheel, other for door lock) - Possible?

[adubya]

Alright, so I'm 85% committed to buying the Stebel Nautilus horn (loud and aggressive, just the way I like it:headbang) since the stock 2010 horn gets me laughed at, but the thing is I don't want to be waking up my neighbours at 2 in the morning when I get home and hit the lock on the key fob twice. So is it possible to keep the stock horn wired for the key fob, and then wire up the Nautilus for the steering wheel horn?

As for the actual install, I found some good walkthrough's online so I'm not overly concerned about that.

[Noisy Crow]

Use a relay. On a standard bosch-type relay, the common (pin 30) switches between the two output contacts (87 and 87a). So: horn lead from the harness to pin 30, stock horn to the NC contact (87a) and the new horn to the NO contact (87). One side of the coil to ground, the other to a wire, fuse, etc. that is hot when the car is on. When the car is running, you get the loud horn. When the car is off and you lock the doors you get the stock horn.

http://www.the12volt.com/relays/relays.asp

[adubya]

Thanks for the walk-through, much appreciated. Looks like I'll be getting one of the guys @ work to help me wire it up.

[Fuyuzora]

Use a relay. On a standard bosch-type relay, the common (pin 30) switches between the two output contacts (87 and 87a). So: horn lead from the harness to pin 30, stock horn to the NC contact (87a) and the new horn to the NO contact (87). One side of the coil to ground, the other to a wire, fuse, etc. that is hot when the car is on. When the car is running, you get the loud horn. When the car is off and you lock the doors you get the stock horn.

http://www.the12volt.com/relays/relays.asp

Thanks for the detailed post, Noisy Crow. If I wanted to do this with twin Hella Supertones, would the resulting circuit be as follows?

http://i51.photobucket.com/albums/f360/bairdga/Hella_Relays_v1.jpg

Also wondering if you can suggest:

i) What switched supply would be convenient to tap into?

ii) Where to buy automotive electrical parts? I have lots of theoretical electrical experience from undergrad, as well as working with solar installs, but never had to buy automotive electrical parts before. I'm thinking somewhere like Princess Auto?

[eguiyab]

I'm actually in the same boat right now. I just picked up the Hella's on the weekend.
From my understanding there is no need for the secondary relay (RED). You can connect the dual hellas to Pin 87 of the "blue" relay and Pin 30 can be connected to the stock horn harness. I haven't tried it just yet... but i will be this weekend.

As far as to where you can pick these relays, you can pick them up at your local canadian tire or princess auto, in the automotive electrical section. Usually close to the bulbs.

[Fuyuzora]

If the Hella relay's not needed that'd make life a lot simpler - I wasn't sure if the stock horn wiring was sufficient to handle the Hellas, so I figured I'd draw the circuit assuming it was necessary.

I'm hoping to get mine installed on the weekend as well, time/weather permitting.

Thanks for the tip on where to find the relays! :thumbsup

[Trini2DeBone]

Keep us updated on the installation guys. I am thinking about adding back my stock horn using the relay. My current setup is the two hellas wired to the horn lead from the harness without relay.

[Fuyuzora]

Couldn't find a Bosch-type 12V SPDT relay at either Princess Auto or Canadian Tire. Going to try PartSource tomorrow but I'm not holding my breath.

Anyone have any other suggestions before I order one online? :S

[eguiyab]

Yeah... I found the same... The relay I used was not a SPDT - HOWEVER, you can still make it work.

http://i23.photobucket.com/albums/b354/eguiyab/Hella_Relays_v1.jpg

Fuyuzora - I hope you dont mind, I edited your diagram.

This is the setup I used using a basic relay from CT. It provides the desired effect of Hella's ONLY on during the car running and stock horn in all other situations. Each Hella Horn could take its own 87Pin if desired, I just happen to run out of connectors so it ended up that way for me.

In my situation my switched source was my FOGLIGHT - its odd I know, but I use my Fogs as my DRL's so they are always on. IT works for now, but I think i will switch it later. One advantage I do find with this, is that IF i dont wish to use the Hella's while the car is running, I can turn them off by turning off my Fogs. In future I think I will run a small switch inside the car for this purpose and use maybe the cigarette lighter or something as the switched source.

With this setup, i find that the stock horn will always be functional. The relay could go bad, the ground could get fouled and the stock horn will be unaffected - So I like this setup in that aspect.
Hope this helps.

[Fuyuzora]

Don't mind at all! Glad it's being useful. :)

That's a clever workaround - if I've interpreted your circuit correctly, the stock horn remains connected to its original circuit, and thus operates when the car is off; when the car is running, the relay also activates, and you now have a triple-horn system, correct?

[Fuyuzora]

Found a relay at The Source in the end. Rated for 30/40A which is kind of excessive, but it should do the trick just fine.

Downside is, I spent so much of the day out and about I didn't get the chance to install anything. :(

[eguiyab]

Don't mind at all! Glad it's being useful. :)

That's a clever workaround - if I've interpreted your circuit correctly, the stock horn remains connected to its original circuit, and thus operates when the car is off; when the car is running, the relay also activates, and you now have a triple-horn system, correct?

Technically, yes - It would be a triple horn system, but the Hella's are SO loud, you would never hear the stock horn anyway.


Found a relay at The Source in the end. Rated for 30/40A which is kind of excessive, but it should do the trick just fine.

Downside is, I spent so much of the day out and about I didn't get the chance to install anything. :(

That's part of the the reason I decided to make due with what I had.... I didn't wanna spend my time searching. Happened to me again today trying to find some loose 4Ga wire. I finally gave up after an hour, cuz i was burning work time.

Good luck and let me know how it goes.

[Darkice]

i wanna see how this turns out i want loud horns ,cause theres so much dumb drivers in btown lol


Found a relay at The Source in the end. Rated for 30/40A which is kind of excessive, but it should do the trick just fine.

Downside is, I spent so much of the day out and about I didn't get the chance to install anything. :(

[Noisy Crow]

Haven't been on for a few days...

For you guys looking for relays at Princess Auto (or anywhere else in NE Mississauga): Sayal has 'em. They are on Matheson, near Dixie. They also have connectors, wire, etc. etc.

You can skip the 2nd relay for the Hellas; the pair draws a good bit less than the stock fuse is rated for. For the switched hot... check out the indy fog mod...

[Fuyuzora]

You can skip the 2nd relay for the Hellas; the pair draws a good bit less than the stock fuse is rated for. For the switched hot... check out the indy fog mod...

Awesome, this should save me a bunch of time/wire/connectors with the installation. Thanks for the tip re: switched hot as well.

Will try to take pictures of my install for a DIY Guide. I know a couple exists here for Hellas, and other exist elsewhere for 2010s (M247), but it can't hurt to add another to the pile. :thumbsup

[Fuyuzora]

Got three-quarters of the way through this and had to stop due to low light. Should be able to finish in 0.5~1 hour tomorrow.

Took a read through the indy fog guide (http://www.torontomazda3.ca/forum/showthread.php?47958-2010-INDY-FOG-MOD-FINALLY-REVEALED), but I'm still a bit foggy as to which circuit I should tap for switched power. Going to try fuse 18/INJ, but I don't quite understand how it's going to be tapped... Hopefully it will make more sense in daylight.

Could someone please advise which circuit to tap otherwise? Thanks!

[Fuyuzora]

After a pile of trouble, got mine working. Tapping into a seafoam coloured line in the wire loom inside the fuse box for the time being. Will probably work out something better in the future, though.

The stock horn sounds a little garbled now... Likely a side effect of having to wire all three horns to the same input, and switching between grounds instead of vice-versa as originally planned. Hellas work as intended though, and the stock horn is a little quieter when locking the car, which is probably a good thing.

Also, despite taking the time to paint my horns (caterpillar yellow), I sadly ended up mounting them on the right-hand side, in front of the washer fluid pump, where they will not be visible.