code alarm ca425 to horn

i have code alarm ca 425 master module already installed. installation initially done buy circuit city.   the siren out is connect to the aftermarket siren. i want to connect the siren output to the factory horn. i found the ca425 manual online and it says that the siren output wire is (-) negative, and i found the wiring diagram for my 2004 dodge stratus (sedan) and the horn wire is (-) negative also located at the steering column harness. could i just take the siren output wire for the ca425 and tap into the factory horn? or would i have to use a relay?

You'll need a relay for sure!

The horn requires too much current and would fry the alarm if you didn't use a relay.

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Houston Texas

There actually should be a (-) horn output from the brain. It's been a couple of years now, but I think it may be BROWN / black. Not too sure though.

There is a horn output, completely independent from the siren. If you don't have the install manual that lists the wire color, I'll find mine and look it up for you.

No relay or any special wiring is required----just get to the alarm brain, find the horn-honk wire, extend it with another wire if the installer has cut it short......

The is a BLACK/ red wire in the steering column harness that activates the horn, but that wire travels through the car's BCM, which introduces a slight delay---you will have some trouble getting a consistent horn-honk when doing it this way, in my experience.

Instead, locate the horn relay, in the fuse box inside the car.

Pull the relay halfway out so that it will still operate, but you can touch a multimeter or test light to the relay's terminals.......

Test for the terminal of the relay which is GROUND when you blow the horn.......pull the relay all the way out......carefully wrap the alarm's horn-honk wire around the appropriate relay terminal, and reinstall.

NOTE 1: To find the correct BLACK/ red wire, OR the correct relay terminal, you'll need a test light or multimeter, and the knowledge to use it correctly. Connecting to things without testing can lead to disaster.

NOTE 2: Also at the horn relay, is another terminal that tests as positive when you blow the horn; that's the WRONG terminal to use. Again, it's the terminal that tests as GROUND that you want.

thanks guys for the replies. just found the master module today and CA sent me the manual via email so i will be looking tomorrow for it.

Worse case scenario you could do this


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Certified Security Specialist
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