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Factory alarm

Old 05-13-2018, 03:48 PM
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kansas123
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Default Factory alarm

My factory alarm quit recently for no apparent reason other than to say Ha Ha to me, so I have been digging into it. The AIM shows a dual plug going to 2 flashers, and a triple plug going to one relay. I removed the relay and opened it up, it's clean as a whistle, and I show proper continuity on the 3 posts. Continuity between 1 & 2 as it is, and it changes to continuity between 1 & 3 when activated. On the dual plug, I only have 1 flasher fuse hooked on, a 170. And it shows good continuity. I am wonder if I am missing (the second) flasher. I mean obviously the 2nd flasher is not there, but it never was to my knowledge. Also, when I turn the (trunk) key to activate the alarm, I can hear the relay make a single noise, and another (different) noise when I turn the key back to deactivate. I unplugged the flasher and used my turn signal flasher in it's place to see if that would make it work but it did not. So I am stuck. All the wiring appears very clean, wiring to the lock and the horn is in good order and attached. I did not check the plug wiring with a meter, but maybe I should? And, would I get a continuous horn if I jumped the flasher plug and activated the system? (this would maybe help me check all the wiring)? Thanks

First pic obviously from AIM, 2nd is flashe and relay in place, 3rd is relay with spades labeled 1, 2, 3, and 4th is flasher.
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Old 05-13-2018, 06:45 PM
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I would say that without you testing and checking your circuits. I cannot be of much help.

I would verify that the horn actually works.

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Old 05-13-2018, 08:24 PM
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GUSTO14
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David, the two flashers you mention (#8 in the picture) are really only one flasher, but there are two different styles, so what you have is correct.

As Dub mentioned, one of the first things I would do is test the horn. You should be able to do this by simply running 12 volts to the spade on the horn, in the drivers's side quarter, behind the inner fender liner. If the horn works then you know you have a wiring issue. If your horn is an original it would not at all be out of the ordinary for to to have failed. I would check that first. Remember that you will need to run both a 12 hot lead and a ground to the horn as it is mounted to the fiberglass inner fender.

This is what it should look like...


Replacements have been non existent for some time, so many are replaced with an otherwise typical looking horn...


If your horn does work, we can move on to trouble shooting the wiring. If it doesn't just substitute any conventional horn and try the system.

Good luck... GUSTO

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Old 05-13-2018, 08:37 PM
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riverracer au
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my 72 has a trumpet style alarm horn up in the rear drivers side fender.
no sound, just a slight click to be heard.
so connected 12v driectly to it and gave it a slight tap, slightly louder brrrp could be heard,
gave it a few more gentle taps, sound kept getting louder n louder.
then in one almighty brrrrrrrp, it made the correct sound....

hint to the wise, wear safety glasses when looking/tapping under there, the speed at witch the dirt/muck came flying out...
ask me how i know.......

same style as my horn

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Old 05-13-2018, 08:50 PM
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Originally Posted by riverracer au View Post
my 72 has a trumpet style alarm horn up in the rear drivers side fender.
no sound, just a slight click to be heard.
so connected 12v driectly to it and gave it a slight tap, slightly louder brrrp could be heard,
gave it a few more gentle taps, sound kept getting louder n louder.
then in one almighty brrrrrrrp, it made the correct sound....

hint to the wise, wear safety glasses when looking/tapping under there, the speed at witch the dirt/muck came flying out...
ask me how i know.......
Thanks for the reminder...

I should have remembered since my experience was close to yours!

GUSTO
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Old 05-14-2018, 03:52 PM
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Originally Posted by GUSTO14 View Post
David, the two flashers you mention (#8 in the picture) are really only one flasher, but there are two different styles, so what you have is correct.

As Dub mentioned, one of the first things I would do is test the horn. You should be able to do this by simply running 12 volts to the spade on the horn, in the drivers's side quarter, behind the inner fender liner. If the horn works then you know you have a wiring issue. If your horn is an original it would not at all be out of the ordinary for to to have failed. I would check that first. Remember that you will need to run both a 12 hot lead and a ground to the horn as it is mounted to the fiberglass inner fender.

This is what it should look like...


Replacements have been non existent for some time, so many are replaced with an otherwise typical looking horn...


If your horn does work, we can move on to trouble shooting the wiring. If it doesn't just substitute any conventional horn and try the system.

Good luck... GUSTO
Thanks, I was going to test the horn this morning but woke up quite under the weather. The horn I replaced several years ago. Maybe later this afternoon I can check that horn. Thanks.
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Old 05-14-2018, 04:56 PM
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Just be aware.

GM did not ALWAYS supply battery voltage to the terminal on the horn. What they did was make the battery voltage be connected to the mounted area and then they supplied as a ground to the terminal to make the horn blow.

SO...If you climb under the car and try to put battery power on the terminal..it will not work IF the housing already has battery power on it.

SO verify this by looking at your wiring diagram....or take it out of the car and then it will work either way.

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Old 05-16-2018, 02:44 PM
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kansas123
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So I removed the horn and tested it with a bench battery and TOOT, it works, I figured it would. Next I will make sure that all the grounds are rust free and good. The horn is wired to the car like the AIM shows: a yellow wire in the harness which attaches to the mounting bolt of the horn, and 2 orange wires that are wired together and plugged into the spade attachment on the horn. I don't know where the other end of the yellow wire goes yet or if that is ground or not.
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Old 05-16-2018, 03:38 PM
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ORAGNE wires are the wires what supply battery power. When the switch in the back of the car is turned ON...the ORANGE wire is now supplying power to the horn.

Then in order for thee horn to TOOT...it is waiting on a ground signal.

The YELLOW wire is the wire that is the controlled switched GROUND. It is NOT a ground wire but it is what is supplying the needed ground to make the horn TOOT.

This is why the wire is YELLOW and not BLACK like all of the ground wires in your car that are really a ground wire.

And many other wires in your car that have ground wires that are being switched and controlled to make something work...they are different colors...such as DARK GREEN, WHITE and LIGHT BLUE come to mind.

DUB

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