Tapping into OEM horn for alarm

[economatic]

Hey everyone. I have a 2008 Yaris sedan and I'm installing an alarm. The installation is complete minus tapping into the horn. I think I found the right lead(s) but I'd like to hear what others did with theirs. The problem with mine is I did the install right before taking the car into the shop to have the drivers airbag replaced (theives stole it) so the horn wasn't operational.

At any rate, I found this (http://www.yarisworld.com/forums/showthread.php?t=9565&highlight=712T) outstanding write up for installing a keyless entry and he tapped into the D3 harness. I found the same D3 harness but there were two other wires--in other words it had black, tan, and pink wires. Anyone else see the additional wires and if so did you tap into them for the horn? FYI, I metered the black one and it showed constant 12 volts. I also read there is a black/light green wire in a 36 pin harness at the fusebox. I think I found it but am less sure about it. That one also showed constant 12 volts.

By the way, I will mention that I had the same 712T keyless entry installed in my car. I chose not to install an alarm as...well...it is only a Yaris and I knew I wouldn't keep anything valuable in the car. Well, in the nicest of nice neighborhoods theives broke a back window, completely ransacked the interior of the car (stole a flashlight? Come on!), and stole the driver's side airbag. My car was the only one that got hit among many expensive cars in the neighborhood. In other words, thieves were looking for cars without alarms. Just something to keep in mind if you're thinking about saving a few bucks by getting a keyless entry vs. an alarm.

[bronsin]

When installing an alarm remember all the trouble its gonna cause. Car wont start, horn wont work CEL goes on and wiper switch works the tail lights.

[Tamago]

When installing an alarm remember all the trouble its gonna cause. Car wont start, horn wont work CEL goes on and wiper switch works the tail lights.

yeah, if you install it like a crackhead.

the switch at the horn is a sinking signal, so you're looking for a GROUND when the horn is pushed. it's at the steering column.

[bronsin]

yeah, if you install it like a crackhead.

.

You mean like tapping into the horn circuit?

[Tamago]

You mean like tapping into the horn circuit?

you apparently don't install alarms

[economatic]

You mean like tapping into the horn circuit?

Wow. Thanks for the completely pointless comments. :clap:

But seriously, I'd just like to know where others have tapped into the horn on a sedan. All the sources I've found have been less than clear about the horn, which I why I skipped it for the keyless entry in the first place.

[Tamago]

why not tap it at the steering column as i've already suggested?

[CTScott]

http://i372.photobucket.com/albums/oo163/ctscott329/Yaris%20Cruise%20Control/ConnD3.jpg

Tap the black wire on the white connector in the picture (yours will probably only have the black wire {no blue and brown}), and like Tamango said, it needs to be grounded to make the horn blow.

[bronsin]

you apparently don't install alarms


No but Ive been up in the middle of the night disconnecting the alarms my neighbors have installed!

[Tamago]

No but Ive been up in the middle of the night disconnecting the alarms my neighbors have installed!

so you're a teef then.

good to know

[economatic]

why not tap it at the steering column as i've already suggested?

Perhaps I wasn't clear in my original question. The write-up I found said there is only a black wire coming out of pin 8 of the D3 harness. In my sedan there are 3 wires coming out of the D3 harness--1 black, 1 light brown, and 1 pink and if I remember correctly the black wire was coming out of a different pin (I think pin#5 of an 8 pin harness). Also, I couldn't test the horn because the airbag and horn switch are missing thanks to the thieves. :mad:

I just want to confirm that this is indeed the right wire so I can call the installation finished. Pretty irritated with the mess of my car these thieves made...

[Tamago]

ah, now it all becomes clear!

sorry i wasted your time haha

[economatic]

ah, now it all becomes clear!

sorry i wasted your time haha

No worries--I wasn't clear in my initial post. Thanks anyway.

[CTScott]

Perhaps I wasn't clear in my original question. The write-up I found said there is only a black wire coming out of pin 8 of the D3 harness. In my sedan there are 3 wires coming out of the D3 harness--1 black, 1 light brown, and 1 pink and if I remember correctly the black wire was coming out of a different pin (I think pin#5 of an 8 pin harness). Also, I couldn't test the horn because the airbag and horn switch are missing thanks to the thieves. :mad:

I just want to confirm that this is indeed the right wire so I can call the installation finished. Pretty irritated with the mess of my car these thieves made...

That really stinks!


The horn should be pin 8 of D3 on the Sedan as well as the LB.

29312

[tomato]

When installing an alarm remember all the trouble its gonna cause. Car wont start, horn wont work CEL goes on and wiper switch works the tail lights.

Not necessarily. My after-market alarm works fine close to a year after install :iono: (knock on wood)

by the way, CTScott, you rock! :headbang::headbang::bow::bow::thumbsup:

[economatic]

That really stinks!


The horn should be pin 8 of D3 on the Sedan as well as the LB.

29312

Awesome! Thanks for looking that up. I must have forgotten how to count since I thought it was an 8 pin harness but it was a black wire and one over from the end so that must be it. I'll give it a shot later in the week when I get the car back from the dealership. I actually tapped that wire when I had everything apart so it should be a quick plug and play after testing.

[Liu997]

Does the module give a constant -12v so the alarm wouldent sound like a normal one, more like crap

[economatic]

http://i372.photobucket.com/albums/oo163/ctscott329/Yaris%20Cruise%20Control/ConnD3.jpg

Tap the black wire on the white connector in the picture (yours will probably only have the black wire {no blue and brown}), and like Tamango said, it needs to be grounded to make the horn blow.

That was a very helpful picture--my employer's internet censors blocked it so I had no idea it was there until viewing the message at home. Thanks again for the detailed info.

Does the module give a constant -12v so the alarm wouldent sound like a normal one, more like crap

The alarm I have can use both the horn and the siren. The horn is a negative trigger so it just gives a blast when grounded (what I was looking for in this thread) whereas the siren is a +12v. If I understand your question correctly you are asking about the tones of the siren, which is in the circuitry of the siren.