What Relay To Use For Aftermarket Horns?

[jj421]

Hi there. I am trying to install a pair of Fiamm Freeway Blasters. I first tried cutting the original horn wires and directly hooking up the new horns. Well, it kinda work. At first, it worked. Then when I reinstalled my head lamps, the horns grounded out, causing them to blare at full volume until the battery is disconnected. Now though, every time I reconnect the negative terminal on the battery, the fuse blows, which without that fuse, the car won't start.

 

Anyways, I'm gonna wire up the system with a relay. I need to know what relay to use, since the guys at O'Reilly aren't sure. Tomorrow, I'm going to a car electronics place (similar to Car Toys, where I will also go), as well as NAPA and see what they have to say. But until then, if you guys have hooked up new horns, what did you do?

 

I found this diagram online for two Freeway Blasters, but it's for a motorcycle, not a car. But is this similar to what I have to do?

 

[1 Lucky Texan]

I dunno, I found this;

 

http://www.scoobymods.com/showthread.php/fiamm-horn-installation-guide-and-19.html?t=19

 

 

also, there is a Civic and a Tundra install video on youtube - maybe someothers.

[jj421]

I dunno, I found this;

 

http://www.scoobymods.com/showthread.php/fiamm-horn-installation-guide-and-19.html?t=19

 

 

also, there is a Civic and a Tundra install video on youtube - maybe someothers.

 

Yeah, but that doesn't say anything about a relay to use. I need to actually wire up a separate relay to get the most sound out of these horns and to make the horns work, period.

[tractor pole]

just use a standard bosch style relay

 

these are readily available from local parts stores,

I always use the bosch ones but there are other brands that do the same thing.

 

Ben

[jj421]

Okay, that's what I was thinking of using, because that's what the wiring diagram I had in the original post had in it. At least for me, the original image is not loading up, but that's what it had.

 

Okay, let me make sure the wiring is correct. A wire goes from the positive terminal of the battery to a 20 amp inline fuse, then to the 87 terminal on the relay. The stock positive wires for the horns go to a y-connector, merging into one wire that goes to the 86 terminal on the relay. The stock negative wires for the horns go to a y-connector, merging into one wire that goes to the 85 terminal on the relay. Wires go from one terminal on each horn, to a y-connector, to the 30 terminal on the relay. And then each horn gets grounded to itself (according to the instructions that came with them). Well, here, I drew up a diagram of what I'm talking about (excuse my handwriting :-p ).

 

 

This is based off what I can find online and whatnot. And thinking about it, the reason why the horns would always blow the fuse when I connected the battery is because the stock horn is a 15 amp fuse, whereas I think I need at least a 20 amp (hence the inline fuse). So I could probably put a 20 amp fuse in there and call it quits, but I'm gonna hook up the relay and whatnot. I hate wiring stuff and electricity, but I also hate being run off the road by a semi who can't hear my horn (I have a video on YouTube of that incident, haha). I definitely want the relay since it'll let the horn be at full volume, and it's probably better for the wiring as well.

 

So yeah, thanks for the relay info. Hopefully I can pick one up at O'Reilly or NAPA. I know O'Reilly doesn't have y-connectors, so hopefully NAPA does. If any bit of my wiring is off, let me know. I think that is how it's hooked up, based on what I can see online. And along with the 20 amp inline fuse to the battery, I'm also gonna swap out the fuse under the dash with a 20 amp, to be safe.

 

Oh, and what gauge wire should I use? I read a lot of 12 gauge wire being used online, so I'm thinking that's what I should use. Have a guess as to how much length in wire I need?

 

Thanks again! I feel like I need way to much help here, haha. Hopefully this'll be the last thing for a while I post on here that I need help with. :-p

[Loyale 2.7 Turbo]

You have it Backwards, the Spade Nº 30 is the IMPUT for the Relay, so the Fused line shall go to it, while the Spade Nº 87 is the OUTPUT from the Relay to the Device (Horns).

 

Have you seen this? ~► Here.

 

I Hope it will be Useful for you.

 

Kind regards.

Edited August 20, 2012 by Loyale 2.7 Turbo
to add the web link to the word: Here. ;)

[jj421]

Okay, thanks for the reply. Yes, after I posted, I found a picture with a diagram for how relays work, and it did say I have it backwards. But it also said that the input and output are interchangeable. But I guess I'll wire it up properly to be sure it will work.

[jj421]

Okay, I went out to NAPA and bought all the stuff I need. Wired it up. I connect the battery, and all is good. Then I press the horn button and nothing happens, besides the relay clicks. My best guess is that the horns aren't grounded, even though the ground wire is directly touching the chassis.

[Loyale 2.7 Turbo]

Well, lets see: if the Relay Clicks, it -usually- means that its internal switch is Working on bypassing Power (+) from Spade Nº 30 to Spade Nº 87.

 

So, if your horns aren't working, one cause could be their Ground, as you wrote; but another cause could be that you Didn't connect 'em both to the Spade Nº 87 on the Relay, or the Fusible to the Spade Nº 30, is Blown.

 

Good Luck!

[jj421]

Well, lets see: if the Relay Clicks, it -usually- means that its internal switch is Working on bypassing Power (+) from Spade Nº 30 to Spade Nº 87.

 

So, if your horns aren't working, one cause could be their Ground, as you wrote; but another cause could be that you Didn't connect 'em both to the Spade Nº 87 on the Relay, or the Fusible to the Spade Nº 30, is Blown.

 

Good Luck!

 

I'm thinking it's the ground, but I'll check the connections. I manged to get a honk from one of the horns when I connected the battery, but it was for a split second and after, the relay just clicked.

 

Both the inline fuse and the fuse under the dash are good, so no worries there.

[jj421]

I think I figured it out. I was grounding the horns to the chassis, whereas I needed to hook up the horn's ground to the OEM negative wire. Did that on one horn, plugged in the batter, pressed the horn, and it worked beautifully. So hopefully doing that to the other side will be the only thing I need.

[Loyale 2.7 Turbo]

Yes... seems like the Chassis on those old Subies isn't passing a Good ground signal for electrical Devices...

 

But let me Ask, which Ground did you used for the Relay?

[jj421]

I am using the negative wires from the original horns as the ground for the relay. If I ground the relay to the chassis, could I ground the horns to the chassis to make it work? Or would that make it so when I touch the negative wire on the battery to the terminal, the horns would just blast? I'm short like 4" of wire to complete the entire circuit.

[jj421]

Sweet! They're hooked up and working, for now. :-p Honked them for my sister to hear, and she jumped a little, haha. Hopefully when I put the head lamps back on and whatnot everything stays connected. Let's just say my wiring is not necessarily professional. Passenger side is okay, but the driver's side has a bunch of wires and I hope the head lamp goes back in without issue.

 

Thanks for your help with it! I probably couldn't have done it without you, haha. I hate wiring stuff up and I am literally scared of electricity and sparks (hope I never have to get tasered one day ). I'm glad I got them working. I learned what a relay is used for, since I didn't know about them before hand. Also learned how to wire up horns and wiring with a relay. Always good to learn something.

[tractor pole]

Sweet! They're hooked up and working, for now. :-p Honked them for my sister to hear, and she jumped a little, haha. Hopefully when I put the head lamps back on and whatnot everything stays connected. Let's just say my wiring is not necessarily professional. Passenger side is okay, but the driver's side has a bunch of wires and I hope the head lamp goes back in without issue.

 

Thanks for your help with it! I probably couldn't have done it without you, haha. I hate wiring stuff up and I am literally scared of electricity and sparks (hope I never have to get tasered one day ). I'm glad I got them working. I learned what a relay is used for, since I didn't know about them before hand. Also learned how to wire up horns and wiring with a relay. Always good to learn something.

 

just make sure that you have a fused wire coming from the battery, all your factory horn wire is doing now is triggering the relay so it is not necessary to put in a larger fuse, the relay harness is carrying the main load of the circuit now.

 

typically it only takes 250mA (1/4 amp) to trigger one of these relays.

The larger fuse in the factory spot can be dangerous, the fuse size is there to protect the wiring not necessarily the light, horn, etc...

looks like you got it figured out anyhow, just some thoughts.

 

Ben

[jj421]

Yeah, I actually tried putting a 20 amp fuse in the fuse box, and basically it didn't register it. The hazards and horn won't work unless a 15 amp fuse is there apparently.

 

Now I've got another small problem, haha. Whenever I put my driver's side head lamp assembly back in, if I touch the negative wire on the battery, the horn just blares. Take the headlight out, it returns to normal. So I guess the horn is grounding out or something. Needless to say, taking the headlight in/out constantly is very annoying.

[Caboobaroo]

On my XT6, I used a fuel pump relay from an EJ harness I had. Cut the pigtail and relay right off the harness and wired it in. Before, the Hella Supertones I have didn't work and I checked the whole system. Installed the relay and works like a champ.

[jj421]

Ugh. Still can't get the headlights in.

 

With headlight out, connect battery. Press the horn button; horn works fine. Put the headlight in. Put the spring in place on the top part of the headlight. Connect battery. Press horn button; horn works fine. Place adjusting screw on the left side of the headlight. Connect battery. Press horn button; horn works fine. Put the side marker light back in it's place. Connect battery. HOOOOORRRRRNNNNNNNN Disconnect battery quickly. Take apart headlight assembly. Tape over any possible spots for the horn to ground itself. Repeat the process.

 

The passenger side headlight is in and aimed, but I can't get the driver's side. One time I almost got it, but I shut the driver's door and the horn started blaring. Ugh.

[whistler]

I don't know, someone else should weigh in, but the loyales are switched ground also, right? So the relay should actually be controlling whether or not there is a path from the horn to chassis ground and the horn will always have a connection to the battery(with a fuse.) The horns are probably getting power from the headlamps (which sound like they are set up switched ground) and you are also giving the horns a path to ground because you wired them "normally" ie with switched + and constant ground. Read the rest of Loyale 2.7 Turbo's post about swapping out the old relays with bosch style if you don't understand the difference between switched ground and switched positive.

 

like this:

 

I drew it in series but it probably doesn't matter either way, one horn might be slightly quieter the way I drew it... probably just keep it wired parallel.

 

Tom

[jj421]

I don't know, haha. It's just the driver's side horn is making contact, metal on metal, somewhere, I suppose. I taped over all the connections, all the metal on the horn, and even most of the headlight. I put it everything back and I guess a connection is off somewhere. Only the passenger side horn works. But that's okay for now since I need the car for work tomorrow, then I got three days off to mess with it. I think if I go in and fix the connection, it should work.

 

The circuitry and system I have wired up seems to work. With the headlight out and the battery connected, it works just like normal. The horn doesn't come on until after you press the horn button. And both horns blare just like they should. But when I put the headlight back in, the moment the negative battery wire touches the terminal, the horn blares. And it's just the driver's side horn; not the passenger side. So that really leads me to believe the horn, or a wire is grounding somewhere when I put the headlight in.

 

Once I take apart the headlight assembly tomorrow/the next day, and I fix the connection, it should work. But of course, with my luck, it won't. But for the short drive too and from work, I have the one horn working in case I need to use it. Sucks because it's the high tone horn, so it sounds just as sucky as the stock horns. :-p I'd say just the one horn is as loud as the two OEM horns. So nothing really gained, but nothing lost. I will say, however, that the times I've heard both the high and low tone horns going at the same time, it sounds awesome! It does sound like a mid-size sedan, or at least something larger. Can't really compare the loudness, since I've already forgotten how loud the OEM horns were, haha.

[Loyale 2.7 Turbo]

By reading your posts, I guess something is wrong there, and could be:

 

• Mismatched Positive - Negative terminals between Horns.
  
• The Switching Ground, instead a Switching Positive.
  

 

Those Subaru's Headlamps comes with a Permanent Positive and the Switch controls the Ground only, so if the Horns are wired the Same by Subaru, maybe one (or Both) horns are "Sending" the Ground signal to the Relay.

 

The Horn body (itself) is isolated from the ground on its metal plate that fixes it to the car's chassis, that is the reason for independent Ground wire and positive wire on a Horn: it is Not Grounded to its metal base.

 

So, if the Horn's body (itself) stays away from the Chassis, it will work normally with the Wiring, but if the Horn's Body (itself) Touches the car's body, in example: Being somehow "Pushed" by the wirings behind / around the Headlamp assembly, it will Ground itself and since it is receiveng permanent positive (Done by your wirings) it will sound.

 

So, I Kindly suggest you to start by "Moving" down a Little the "Self-Sounding" horn and see if that trick works for you.

 

Also: Remember to properly isolate all the Wirings with enough electrical Tape.

 

Kind Regards.

[jj421]

By reading your posts, I guess something is wrong there, and could be:

 

• Mismatched Positive - Negative terminals between Horns.
  
• The Switching Ground, instead a Switching Positive.
  

 

Those Subaru's Headlamps comes with a Permanent Positive and the Switch controls the Ground only, so if the Horns are wired the Same by Subaru, maybe one (or Both) horns are "Sending" the Ground signal to the Relay.

 

The Horn body (itself) is isolated from the ground on its metal plate that fixes it to the car's chassis, that is the reason for independent Ground wire and positive wire on a Horn: it is Not Grounded to its metal base.

 

So, if the Horn's body (itself) stays away from the Chassis, it will work normally with the Wiring, but if the Horn's Body (itself) Touches the car's body, in example: Being somehow "Pushed" by the wirings behind / around the Headlamp assembly, it will Ground itself and since it is receiveng permanent positive (Done by your wirings) it will sound.

 

So, I Kindly suggest you to start by "Moving" down a Little the "Self-Sounding" horn and see if that trick works for you.

 

Also: Remember to properly isolate all the Wirings with enough electrical Tape.

 

Kind Regards.

 

Thanks for the reply. I know for a fact that the horns themselves aren't polarity conscious, as it states in the manual. I can quadruple check my wiring when I get the headlight out again, as there may have been a chance I did something wrong.

 

I do believe that the horn is grounding on the light itself. I will say that the horn on the driver's side is not as far down as the other one, but that's because I cannot push it any farther down. I don't know if there is less space or the horn is bigger, but it's definitely a tighter fit than the other. That being said, I have gotten pushed down far enough that it seems like the headlight is clearing it. Not to mention all the metal parts on the horn are covered with tape, and now all the parts on the headlight itself where it can make contact are covered with tape. Last time I had the assembly out, I did notice the bottom side of one three way connector was exposed. I taped that over, but again, a connection must be off because the horn isn't functioning. I do believe it's a connection that's grounding itself, considering pretty much all the connections are around the headlight (except for the relay, of course). As far as I can tell, everything is taped over. But I just gotta fix the connection and try again.

[Loyale 2.7 Turbo]

Alright.

 

When I installed the Dual-Tone Bosch Horns onto my Subaru "BumbleBeast" very Long years ago, I installed 'em without a Relay and they has been working pretty well, Flawlessly since the install, but I noticed that those Won't be as Loud as they could be, without a Relay.

 

When I installed those Horns, I placed 'em with their metal plate Down from the Screw on the Subie's body, so they're Hiding behind the front Bumper and by that placing, they doesn't interact with anything around.

 

Did you placed your subie's New Horns facing up from the Screw?

 

If so, you can loosen that screw and place 'em upside Down, so they'll Hide behind the Bumper.

 

Good Luck!

Kind Regards.

[jj421]

I got these to work without a relay, but the horns grounded themselves when I put my light back in. The relay doesn't necessarily seem to make them louder, but I might have gotten used to them and forgot what my old horn was like. I do know, though, that when both horns work, it vibrates the car, like a rumbler siren, which I think is really cool. It's much more noticeable and sounds like a larger car.

 

But see, these new horns aren't where the old ones were. The old ones were at the very edge of the car; pretty much under the side marker light. These ones won't fit there. There is a bumper support beam (I believe) right underneath the headlights, and I'm placing the new horns in the bumper on the other side of that (if that makes sense). So basically, I'm pushing the new horns in the bumper like the old ones, just in a different place. Although, now I'm thinking I should move it elsewhere. Keep the passenger side horn where it is, since it's working fine, but mover the driver's side underneath the grill, or maybe behind it. I think that's what I'll try. Shouldn't affect the sound too much.

[1 Lucky Texan]

is the body of the horn metal? If so, they may be polarized in the sense that the negative wire is also connected to the metal body of the horn. Check with ohmmeter - might have to push through some paint.