connections for a pulsed horn output
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=13749
Printed Date: July 04, 2025 at 6:56 AM
Topic: connections for a pulsed horn output
Posted By: raceman17
Subject: connections for a pulsed horn output
Date Posted: May 20, 2003 at 6:59 AM
Hey Folks
I have a small problem with my car alarm. I wanna add the factory horn with the alarm siern. I have a constant output from the brain to run the siern but, I need to have a pulsed output for the horn, so, it won't burn up. I've looked at the relay section on the webpage and when i use the 12 volt flasher for the pulsed output, all I get is a constant horn. The horn needs a negative input for it to operate(Ford Mustang). This is how I have it set up using two relays.
86 connected to + siern output from brain
85 connected to ground
87 connected to 12V+
30 connected to X on flasher
using another relay to change polarity, I have comming from the L on the flasher to 86,
85 and 30 are connected to ground and
87 connected to the horn which is a negative input.
This did not work and gave a constant horn output so, I moved the flasher in between the 87 and horn connection on the last relay and, it still gave a constant output. Any help would be appreciated.
Thanks
Aaron
Replies:
Posted By: cpgoose
Date Posted: May 20, 2003 at 7:14 AM
This is the diagram that I used to do exactly what you're trying to accomplish...except replace that light with your horn in the diagram.
I think the only difference I had from that diagram (which you'll probably have to do, too) is I put pin 87 to ground instead of 12v+...this is because my horn needed a negative signal to work.
Write back with your results. Good luck!
Posted By: raceman17
Date Posted: May 20, 2003 at 9:20 AM
Do I still need to add a diode in line with the alarm so it doesn't fry the brain of the alarm. If so, would I install it in between pin 86 and the brain module. thanks
Aaron
Posted By: cpgoose
Date Posted: May 20, 2003 at 9:22 AM
I didn't use one...I don't think you need to. You're only working with the siren's wire....not any sensor wires or anything that will be sent back into the alarm (that's if you hook it up correctly  )
Posted By: raceman17
Date Posted: May 20, 2003 at 11:30 AM
cpgoose,
Thanks for the help. I will try your suggesetion tonight when I get home from work. I will post an update soon.
Thanks
Aaron
Posted By: raceman17
Date Posted: May 20, 2003 at 9:43 PM
cpgoose,
I removed one of the relays I was using and I connected everything how it is shown in the above diagram Except I changed the 87 pin to ground. This still did not work. I double checked everything and when the alarm goes off, it is still a constant horn blast. The website (the12volt) says my horn wire is a yellow(-). I took the sterring column apart and I connected the output for the alarm to a different color wire. This wire, when connected had the horn honk so, I figured it was the right one. Could this be the problem? Also, I hooked the flasher up to a light and it worked so, I know it is good. I think everything is connected right but maybe I have found the wrong wire in the steering column. What do you think?
Thanks
Aaron
Posted By: cpgoose
Date Posted: May 21, 2003 at 8:23 AM
Hmmmm, what year is your car?
What type of alarm do you have? Maybe there's something different about the signal the siren is working on. Do you know if it's outputting a positive signal to work the siren?
Posted By: raceman17
Date Posted: May 21, 2003 at 9:49 AM
cpgoose
The alarm is a Omega K-9 Classic. The siren output for the alarm is Positive. The car is a 94 ford mustang. I took and extra relay that I had a connected it as shown above to a light, and it worked properly. So, I know, I know how to hook it up correctly. But, when this is added on the car, all the horn will do is a constant blow. The alarm is set for a constant output for the siern also. Could I have the wire coming from the flasher hooked up to the wrong wire coming from the horn?
I have no clue. If all else fails, I guess I could run a wire from the flasher up to the horn in the engine compartment. I dont know. What do u think?
Thanks
Aaron
Posted By: cpgoose
Date Posted: May 21, 2003 at 10:54 AM
Ok, I'm going to ramble a bit to see if we can figure this out:
1. When you connected the extra relay to a light, and you said it works....are you saying you hooked up a relay and a flasher to your alarm and to a light, and the light actually flashed?
2. Since your horn is constantly blowing...I guess you have found the correct wire....so going to the horn's wire in the engine compartment will only be the same thing. Hmmm....on the 12volt's site, it says the horn is a yellow(-) wire. I also checked on bulldog's website, and that says you have a yellow/light green (-) wire, and designtech's website says the same thing. Maybe that could be it...do you see any yellow/light green wires down there?
3. If you do in fact have the correct wire, it sounds like it has to be the wiring of the flasher. Are you using a 12v flasher with 2 posts on it? Do you have the X and L hooked up correctly?.....with X going to the relay, and L going to the horn's wire?
4. Are you sure you tapped the positive wire of the alarm's siren with pin 86 of the relay? I tapped the siren's red wire in my car...not the alarm's brown wire that goes to it. That probably doesn't make a difference, but just showing you what I did.
5. Here's a post from when I helped someone with this before. It basically just says everything you and I have been saying. I was just reading it to make sure everything was the same. In there, it says that (for my car), my horn shows (-) in the diagram (just like yours does). But when I tested it, it rested at ground. So I guess what the (-) means is that it needs (-) to sound. But I think you're doing this all correctly because your horn is actually sounding...its just not "flashing". Hmmm...
6. When the alarm sounds (by the way, how are you testing this....are you hitting PANIC?)....does the flasher at least click? Can you feel it trying to work if you hold on to it?
Posted By: raceman17
Date Posted: May 21, 2003 at 11:16 AM
Cpgoose,
To answer your questions
#1 I hooked the relay to an extra car battery outside of the car and this worked.
#2 I havent looked yet because I removed the air bag and found a purple wire that showed ground when connected. I will look tonight when I get home from work.
#3 Using a two post flasher. I tried the flasher both ways still with a constant horn blow
#4 The brown wire is connectd to pin 86
#5 yes this
#6 I am hitting the panic button to set it off. The flasher when I hold it in my hand is not ticking or clicking.
Does this Help?
Thanks
Aaron
Posted By: cpgoose
Date Posted: May 21, 2003 at 11:39 AM
Hey, (going by #6) so maybe it's the flasher. Is it brand new? I think you're supposed to be able to feel something...like a clicking or something. Maybe the flasher is bad? Heck, maybe I'll just go run out into the parking lot and set off my alarm, and see if the flasher is clicking. Maybe that's it?
Posted By: raceman17
Date Posted: May 21, 2003 at 11:51 AM
cpgoose,
I have alot of old flashers from old cars (I have alot of old cars that I use for circle track racing) but, they all work when connected to a light and flasher.
who knows, i guess i will look for the correct wires in the column.
thanks
aaron
Posted By: cpgoose
Date Posted: May 21, 2003 at 12:00 PM
You have a lot of old flashers or old relays?
Yea, maybe look for that other wire, too.
All I did was run to the local AutoZone, and bought a 12v car relay for like $2.00. I would say if its not clicking, then it's probably busted.
Good luck.
Posted By: CutDog504
Date Posted: May 21, 2003 at 6:03 PM
I've had this EXACT problem before. I'll tell you exactly how to fix it. You see, the flasher will only actually "flash" if it sees a load(light, horn, etc.). Thats why you said the flasher worked when you connected it to a light, because it saw a load. The reason it wont work on the horn though, is because that negative wire you are connecting it to, is actually the negative trigger from the horn button to the factory horn relay. This wire only triggers a relay, thereore doesnt actually have a "load". To get a load on the horn wire, you have to interface after the relay, most cases, under the hood. To get it to work properly, connect it just like the diagram said, but connect it to a positive horn wire under the hood. I guarantee this will work!!! Believe me, its happened to me several times, and this always solved the problem. Also, you said you got a plain old 2dollar flasher from autozone. Go ahead and upgrade to an electronic flasher. They should be on the same rack near the $2 flashers. They last much longer, work better, and give a consistent flash rate every time. TRY THIS, AND LET ME KNOW IF IT WORKS!!! Even if you wanna test it first, just run a wire outside the car to the horn to test it.
Posted By: raceman17
Date Posted: May 22, 2003 at 7:03 AM
CutDog504,
Do i need to leave the wiring from the (this is how mine is) pin 87 and 85 to ground or do i need to connect it like it is shown in the diagram with 87 being positive and 85 ground? I appreciate your suggestion and, I will try this tonight when I get home.
Thanks
Aaron
Posted By: CutDog504
Date Posted: May 22, 2003 at 8:55 AM
Do it exactly like in the diagram from cpgoose. With 87 on a positive and 85 on a ground. But first you have to find where your positive horn wire is. This is where you interface the wire from terminal "L" on the flasher. Double check to make sure the wire is positive. Put a test light on the wire under your hood going to the horn, and have an assistant press the horn button, the test light should light up if its the correct wire.
Posted By: raceman17
Date Posted: May 22, 2003 at 9:08 AM
cutdog
No problem, I will try this tonight. thanks
Aaron
Posted By: raceman17
Date Posted: May 23, 2003 at 7:02 AM
Cutdog504 and Cpgoose,
Thank you, thank you, thank you. Last night I hooked the said wires up correctly on the otherside of the horn relay and BAM, no problem, works like a charm. I appreciate all of your help.
Thanks
Aaron
Posted By: cpgoose
Date Posted: May 23, 2003 at 7:17 AM
wahoo! Glad it finally worked.
Cutdog, I've never heard of that before.
Raceman....did you connect to the horn's wire under the hood, or did you find the horn relay and just go right after it?
Good job....welcome to having a very unique-sounding alarm :-)
Posted By: raceman17
Date Posted: May 23, 2003 at 8:38 AM
I went directly to the fuse panel under the hood and found the horn relay. I connected the wire on te other side of the relay. If I went for the horn, it was tucked away under the LF fenderwell. (real pain in the butt to remove, I suppose) but anyways, IT WORKS now, the siren goes off and the horn honks. Just like I wanted it too. Thanks guys
Aaron
Posted By: CutDog504
Date Posted: May 24, 2003 at 12:27 AM
SEE?? I told you so, lol!
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