Replacing Horns on 06 Prius

pviebey · Jan 28, 2007

Hi! I've gotten enough off of here, so I thought it was time to give some back.

Just installed Hella horns (from Griots Garage) in my 06 Prius. The notes I found reflected working on a 04, so thought I'd share what I found out...

First - ack! No pictures! Camera battery was dead. When I do my wife's car (05), I'll update and add pictures. Til then, it's word pictures....

Second - NO WARANTY! If this makes your car or garage blow up, or neuters your dog, or whatever, that's all on you. This is just my experience. Use at own risk. Projects in mirror appear closer than they are...

You need a 12 mm and 10 mm sockets and crescent wrenches, flat and Philips screwdrivers. A couple of wire ties and some electrical tape is handy.

Make sure you have spare (male and female) spade plugs.

Remove the black plastic cover over the radiator top. There are black screwie thingies you can start with a Philips and then pop out with your fingernail. I found it easiest to get one out, then lift the cover while turning the Philips and it'll pop the next one, then on to the next one, etc. Eventually, this cover comes off completely. This plastic cover is right above and slots into a painted piece below it (hereafter called the 'painted part').

Remove the 2 black rubber bumper thingies (supports for the hood) on the painted part. There are also several black plastic thingies you can start up with turning a flat plastic screwdriver in a slot on the front, then pop out with your fingernail. You can now move the painted part back to reach in (and you'll need to - often - ). It's fairly flexible, and the paint is pretty hardy, so just lift it back. Don't get crazy, but I have big hands and had no problem reaching in

Now, look down into where the latch is for the hood. See the round object bolted onto the bracket? It's a flattish round thing (that's the horn you're replacing). You can see the bolt to the left of the hood that holds it in place. Use your 12 mm socket to undo the bolt. Try not to drop the bolt or it's washer down where you'll have no fun picking it back up. Now, the horn will fall down. Bummer. Good time to go drink some tea.

OK, we're back. The connector for the horn looks special, but it really isn't. Push in on the tab, and pull on the connector (NOT THE WIRE!), and it'll come out. It's pretty tight...wiggling helps. Now, when you get it out, you discover it's just a special way to do a spade connector!!! So, you can re-use this connection just with a regular spade connector. A little bit of wriggling (and some scraped skin), and you can get it out the top.

Now, look to the left. You'll see right above the painted part another 12mm bolt. Look below it and you'll see another roundy flat thingie. That's the other horn. Use the 12mm crescent to remove the bolt and not drop the bolt or it's washer. Remove that horn the same way (and it has the same reusable spade connector). Put the bolt back in and tighten it down (you don't need it for this use, but might want it for something later...)

OK, hornectimy is now done!

You're gonna need a ground for your horn. Look in the left side of the engine compartment, and you'll see a 10mm bolt with a black wire connected to it, pretty much directly above the horn you just removed. Use the 10mm socket to remove that, and use that for your ground. Route the wires around and under, be careful they won't chafe. You'll need to run this over to the center where the first horn was. You need to put a female spade connector on the wire.

Now, no way would that big Hella horn go back where the second horn was. So, I made a horn 'stack', so both are placed in the center. Each horn has 3 metal plates in a stack to make its bracket, with a hole on the end. I removed the metal plates from each horn. Now, put 2 metal plates on one horn and tighten it down (I used some threadlock to make sure it stays). Take the other horn, and put in on the other end the bracket. but facing the other direction (one horn faces north, one faces south). Add 2 metal plates, and tighten it down (threadlock). It looks like this when done: Horn facing south - 2 metal plates - horn facing north - 2 metal plates (with the hole for me to mount it). Basically, it's a horn assembly with horns on either side and a bracket to attach it.

Let's try dry-fitting it before we do the wiring. Wiggle it into the space by the hood latch (hold back that painted part to get it by). Now, basically, you need to stick both hands in there, one to the left of the hood latch, one to the right. Wiggle it over - the objective is that one horn faces the passenger side, and will just barely fit into the space between the radiator and an aluminum beam. The other faces the driver side (it uhh has to, since it's facing the other way...) You should have that bracket facing up, and it'll fit nicely into the hole for the bolt that held the original horn.

You need to get a ground to each horn (surprise, apparently they're not polaized). I used the nifty y-shaped connector included with the horn to wire them together and give me a handy male spade connection for that ground wire I ran earlier. It was just the right length to go between the horns.

You need to extend the second horn connector (the one not near the latch) over to the horn. So, you need a length of wire with a male spade on one end (for the plug), and a female on the other (for the horn). I connected it to the horn and left the plug end loose when I installed.

OK, let's install in. Wiggle the horns back in like when we dry-fitted them. Put the bolt (and washer) to hold it in place. Tighten down (now I had to use the 12mm crescent because the horn was in the way). Connect the ground connector. Plug the wire into the left (second) side horn connector and also connect the wire for the horn in the center (first). Doesn't make any difference which goes where, but I found the lower horn fit perfectly for the center (first) horn plug.

Push the horn. Should be loud...

Take a break! You deserve it, and it's downhill from here...

OK, now, let's clean up. Wire tie or use electrical tape to neaten up your wiring. This also keeps it from flapping around, and maybe wearing out the insulation (so it shorts out).

Let's reattach the painted parts. Put back the 2 rubber bumpers. Push the black thingies back in, and snap them down.

Put the black plastic part back in (don't forget to put it under the lip of the painted part). Put those nifty Philips head holders back in. Turn them a bit to make sure they're in.

OK, we're all done!

My horns came with a relay. I don't think I need to use it and so far that's been true. If you start blowing fuses, then you need to use a relay....

Hope it helps.

Pat

darelldd · Jan 28, 2007

Great write-up, Pat! As entertaining as it is informative.

Pictures would just be dreamy. Especially of your N-S double horn assembly tree!

Clar · Jan 29, 2007

thanks for the detailed instruction note. how loud is the horn? much louder than regular?

thanx.

Tom_06 · Jan 29, 2007

<div class='quotetop'>QUOTE(Clar @ Jan 29 2007, 01:32 AM) [snapback]382189[/snapback]</div>

thanks for the detailed instruction note. how loud is the horn? much louder than regular?

thanx.
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I put those same horns from Griot's into my '06 a year ago. In a side-by-side comparison with another '06 Prius in my company parking lot, I wouldn't say the horns are more than barely louder than the originals. They do however sound way better - not the tinny beep-beep of the OEM horns.

Mine lasted for about 7 months until one quit working, then I hit a deer and crushed the other one. I have the original horns back in and am waiting on some Lexus premium horns from Sigma for my next try.

I liked them while they worked, but since I rarely use the horn, it was rather expensive on a beep/$$ basis.

- Tom

pviebey · Jan 31, 2007

I think they're a bit louder. The tone is certainly more attention getting (and less wimpy sounding). It says '118 db', but not at what range. The fact they're sideways doesn't help (you could get fancy, and turn the bracket).

I have a Db (sound meter). I was lazy on that too, and promised when I did my wife's I'd do before/after sound level testing. I may also play with turned/not turned...

pat

car · Feb 17, 2007

I just replaced my stock horns with the Toyota JDM premium horns from Sigma auto. Your instructions were really helpful. Thanks!

HTMLSpinnr · Feb 17, 2007

Relays aren't just for the fuses, but to save the poor horn switch from arcing under the high current. After a while, arcing can pit the switch contacts and leave the horn button in a less than useful state.

MGM · Feb 18, 2007

<div class='quotetop'>QUOTE(car @ Feb 17 2007, 02:33 PM) [snapback]392121[/snapback]</div>

I just replaced my stock horns with the Toyota JDM premium horns from Sigma auto. Your instructions were really helpful. Thanks!
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How do you like them? I'm thinking about getting them too. Were they pretty much plug and play or did you have to do any modifications or rewiring? Including S&H, what was the total cost?

Thanks

car · Feb 19, 2007

<div class='quotetop'>QUOTE(Mean Green Machine @ Feb 18 2007, 10:32 PM) [snapback]392645[/snapback]</div>

How do you like them? I'm thinking about getting them too. Were they pretty much plug and play or did you have to do any modifications or rewiring? Including S&H, what was the total cost?

Thanks
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They sound great--a definite improvement. They are pretty much plug and play except for the fact that they don't mount in exactly the same place as on the instructions (which are for the Japanese prius). But even with the Japanese instructions it only took about 20 minutes to install them. I don't recall exacly what S&H cost (I ordered a few other things along with the horns), but the horns themselves cost $69.

geodosch · Jun 23, 2007

I got my Prius two weeks ago, and did my first mod on it this past week: replace the horns. The instructions from pviebey were a huge help (Thank you!!!).

The horns I used were "Blazer Horn" from Tiger Accessory Group, which I purchased at AutoZone, P/N BH101LC & BH101HC (low tone & high tone), which were $29 for the pair (the two were sold separately)

They had a larger pair available of the same make, but I wasn't sure if I would be able to squeeze the extra size into the same space. Fortunately, the pair I got fit right in. In fact, the supplied bracket was identical to the one holding the factory horns in place, so it was like a 1-for-1 replacement. Even the electrical connector slid right onto the terminal of the new horn.

When I saw the gauge of the existing horn wire, I wondered if I was going to have to install a relay. Unfortunately, the new horns did not specify their draw, other than to indicate they needed a 10 Amp fuse. Since that's the size of the Prius horn fuse, I thought I should be okay.

A couple of installation tips:

Make sure you position the horns with the trumpet opening facing down and/or rearward, so they don't collect water

The brackets have different sized holes on each end. The end with the small hole goes onto the horn (this might save you some unnecessary unbolting/rebolting :wacko: )

A short socket extension stuck into the catch of the hood safety latch helps to keep the handle out of the way while working on the horn.

Positioning of the horns was the hardest part, to get them where the connectors would clear the brackets and other body parts, and the trumpets were not facing up or forward. It's a good idea to test the fit before fully tightening the horns to their brackets. Photos are attached to indicate how I positioned mine.

Left (or Center) horn photos

This shows the angle of the bracket relative to the terminals and trumpet
[attachmentid=9158]

The horn is installed in this orientation (the bracket is pointing straight up)
[attachmentid=9159]

Here it is installed. The hood safety latch is raised for a better view.
[attachmentid=9160]

Right side horn

Here's the bracket orientation
[attachmentid=9161]

Horn installed
[attachmentid=9162]

When connecting the hot lead to the right side horn, leave the bracket bolt loose until the connector is on, otherwise there isn't room to maneuver it. You'll also have to bend the terminal very slightly towards the center, so it will clear the piece behind it.

With these horns I certainly won't be mistaken for a semi, but at least my Prius no longer sounds like a squeak toy!

growltiger · Aug 22, 2007

<div align="left">I purchased and installed the JDM Premium Horn. I had a question about the installation. Clearly the horn requires a different installation than that specified for the Japanese model.

So here is my take on the installation and then a question. In my 2007 Prius, there are two horns. Each horn has a wire harness connected to it. I found that the JDM horn orientation required adjustment in order to get the trumpet to point down (so as not to collect water or other debris), so I adjusted them. I used the wire harness from the old horns and attached them to the new horns.

My question is should I have daisy chained the JDM horns as is illustrated or was it okay to use the existing connectors? I can hear the horn and it sounds different, but I cannot tell if both horns are operational. Do I just take it on faith they both work or is there an easy way to verify correct installation?

Thanks to any who reply.</div>

geodosch · Aug 22, 2007

<div class='quotetop'>QUOTE(Growltiger @ Aug 22 2007, 06:04 PM) [snapback]500621[/snapback]</div>

My question is should I have daisy chained the JDM horns as is illustrated or was it okay to use the existing connectors? I can hear the horn and it sounds different, but I cannot tell if both horns are operational. Do I just take it on faith they both work or is there an easy way to verify correct installation?
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I don't know how the JDM instructions show the wiring, but when you say 'daisy chained', I'm assuming you mean in series:

-----[horn 1]-----[horn 2]------>>

as compared to in parallel:

+---[horn 1]------>>
|
+---[horn 2]------>>

Generally putting them in parallel is better, since you don't get the current drop you do having them in series. However, if the horns are designed to be in series, you could overload them wiring them in parallel, which is what you're doing using the existing wiring. Though I would find it very surprising if the latter was the case.

As far as checking whether they're both working, twin horns sound very different than a single horn (assuming you got one high and one low tone, which is the norm.) So if you disconnect one of them and there's an obvious change in the sound, you can be sure they're both working.

growltiger · Aug 23, 2007

<div class='quotetop'>QUOTE(GeoDosch @ Aug 22 2007, 03:37 PM) [snapback]500646[/snapback]</div>

I don't know how the JDM instructions show the wiring, but when you say 'daisy chained', I'm assuming you mean in series:

-----[horn 1]-----[horn 2]------>>

as compared to in parallel:

+---[horn 1]------>>
|
+---[horn 2]------>>
Generally putting them in parallel is better, since you don't get the current drop you do having them in series. However, if the horns are designed to be in series, you could overload them wiring them in parallel, which is what you're doing using the existing wiring. Though I would find it very surprising if the latter was the case.

As far as checking whether they're both working, twin horns sound very different than a single horn (assuming you got one high and one low tone, which is the norm.) So if you disconnect one of them and there's an obvious change in the sound, you can be sure they're both working.
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<div align="left">Time to draw distinctions, eh? Okay, I am game. The JDM horn kit provides a wire harness to connect the two horns therein supplied. Why? Because it appears that the Japan Prius has only one horn. So the original setup is that there is a wire from somewhere that connects to the horn. You install the two horns and connect them with the supplied pass-through cable.

Let me try to schematize this. The original Japan Prius setup (given the supplied instructions) is this:

+-----[horn 1]------>>

After the JDM install, it is something like this:

xxxxxxxxx|----->>[horn 1]
+-----[harness]
xxxxxxxxx|------>>[horn 2]

(Ignore the x's as whitespace is not allowed.)

So I suppose that is parallel.

Now in my 2007 Prius (Tour Pkg 6), the setup is like this:

+----->>[horn 1]
|
|------>>[horn 2]

The installation then requires that one swap out the factory horn with the premium horn. It also required me to rotate the bracket from the factory setting in order to have the horn point down so as not to turn it into a water or debris collector.

Okay, so I suppose the point of this point was to see if this matched the experience of others. I was not happy about mucking with the bracket direction but with slight effort it seemed to allow repositioning. Since I cannot stand by the horn when I test it I am assuming that this works. There is a sound and it does have a richer resonance so there is that.

One last item that I will mention is that the Japanese instructions suggest pulling the front bumper along with removing the top cover. I did not do that as I found sufficient room to detach the original horn and insert the new horn by just removing the top cover. The installation would have taken about 30 minutes had I not spent about another 30 minutes contemplating the bumper removal and then discarding that step as unnecessary.</div>

geodosch · Aug 23, 2007

Growltiger,

Yes, that would be considered in parallel (BTW, the term 'daisy chain' describes a series of serial connections, which is what threw me.)

From what you describe, I'd say you shouldn't even need the harness, since the US Prius already has separate connectors for each horn. As far as taking the bumper off, unless the JDM horns are very large, I have no idea why they would suggest that. I had no problem getting mine replaced with only removing the plastic cover.

growltiger · Aug 24, 2007

<div class='quotetop'>QUOTE(GeoDosch @ Aug 23 2007, 01:06 PM) [snapback]501180[/snapback]</div>

Growltiger,

Yes, that would be considered in parallel (BTW, the term 'daisy chain' describes a series of serial connections, which is what threw me.)

From what you describe, I'd say you shouldn't even need the harness, since the US Prius already has separate connectors for each horn. As far as taking the bumper off, unless the JDM horns are very large, I have no idea why they would suggest that. I had no problem getting mine replaced with only removing the plastic cover.
[/b]
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<div align="left">Nor did I. I just wanted some positive reinforcement.

As for the 'daisy chain,' I think that describes the Japan Prius installation. There is one connection shared by two horns. Interesting that there is but one horn.</div>

patsparks · Sep 18, 2007

If you use a relay and bring the power from the main battery power bus bar via an inline fuse to the relay then direct from the relay to the fuse you achieve 2 advantages over using the original loom to power the horns.
1/ You can use bigger wire so have less voltage drop to the horn making the horn even louder!
2/ You will extend the life of the expensive horn switch in the steering wheel if Toyota haven't included a relay already in the horn circuit.

KK6PD · Jun 8, 2008

pviebey said: ↑

Hi! I've gotten enough off of here, so I thought it was time to give some back.

Just installed Hella horns (from Griots Garage) in my 06 Prius. The notes I found reflected working on a 04, so thought I'd share what I found out...

You need a 12 mm and 10 mm sockets and crescent wrenches, flat and Philips screwdrivers. A couple of wire ties and some electrical tape is handy.

Make sure you have spare (male and female) spade plugs.

OK, hornectimy is now done!

Pat
Click to expand...

So I am sitting here with my new set of horns, and I am wondering "Just how hard is this install gonna be??" I Search and check the Chat, see your post, even with no pictures, it took me about 30 minutes to complete the hornectimy!!!

THANK YOU PAT!!! Your post was well written, exactly to the point and it works!

Now I am not embarrassed to hit the horn when I need to!!!

ATTA BOY PAT!

Barcelona Red Rocks
73 de Pat KK6PD

m2mazda6 · Nov 30, 2008

Just put mine on, Ive had them for a couple weeks now, finnally got them on was pretty easy even for me I have two left hands, just getting your hands in there but works good. not the wimpy horn that was on it. took under a hour to do,

Replacing Horns on 06 Prius

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Replacing Horns on 06 Prius

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Attached Files:

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