air horn circuit diagram is it correct?

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Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=93159
Printed Date: April 18, 2024 at 10:59 PM

Topic: air horn circuit diagram is it correct?

Posted By: iblis
Subject: air horn circuit diagram is it correct?
Date Posted: April 20, 2007 at 10:17 AM

Hi all,

I've drawn up a circuit diagram before installing my electric air horn. I've drawn my modifications (in red) onto the car's wiring diagrams. Does my approach make sense? Is there anything missing/unnecessary?

Sorry bit of an electrical newbie. The idea of the switch marked with the big black arrow is: when open, only stock horn responds to pressing the horn button; when closed, both respond.

Thanks in advance!

https://mr2oc.co.uk/modules/coppermine/albums/userpics/14067/nautilus.gif

Replies:

Posted By: iblis
Date Posted: April 20, 2007 at 10:27 AM

That earth to the right of the relay shouldn't be there... I was sure I erased it! posted_image

Posted By: iblis
Date Posted: April 20, 2007 at 10:30 AM

"Correct" diagram below:

https://mr2oc.co.uk/modules/coppermine/albums/userpics/14067/nautilus2.gif

Posted By: hotwaterwizard
Date Posted: April 21, 2007 at 5:44 PM

Please Explain why you need a Relay. ????>??????

An air horn Solinoid uses about the same current as the Relay. Why do you need a Relay. You only need a Relay for a Regular horn.

posted_image

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: hotwaterwizard
Date Posted: April 21, 2007 at 6:06 PM

Here is a simpler diagram.

posted_image

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: hotwaterwizard
Date Posted: April 21, 2007 at 6:43 PM

Keep it Simple.

Less problems that way.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: hotwaterwizard
Date Posted: April 21, 2007 at 6:51 PM

Even Better!

posted_image

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: dualsport
Date Posted: April 21, 2007 at 7:52 PM

If the air horn shown in the original diagram is the actual compressor and not a relay, then it does draw a lot of current, so that may be why the separate 20A fused circuit was added to supply the air horn.

In any case, the control for the air horn has to come from the right side of the horn connections, like Hotwaterwizard shows, because the other side is grounded. Adding that diode in line with the RH horn will do nothing; though it might seem like the current flows that way and you could tap off the signal from the diode output, it doesn't work that way. Once it hits ground, it's ground.

If the box shown for the air horn is supposed to just be a separate relay controlling the air horn compressor, then simply wire it as shown by Hotwaterwizard; if not, then just add a relay. No need for any diodes, because you're not dealing with any electronic drive circuitry and don't need to isolate anything.

Posted By: iblis
Date Posted: April 22, 2007 at 6:50 AM

Hi all,

Thanks for all the replies! As above, I'm not very experienced with this stuff, so apologies if any of the below is crazy talk posted_image

The airhorn box is an electric compressor (should have been clearer about that). The switch is to go in the cabin, so I figured the relay would be a good idea rather than wiring higher gauge cable all the way through to the cabin.

I'm not sure if the existing horn wiring is high enough gauge to safely carry the compressor's current, so that's why I put a seperate 20A fused feed.

Are either of those correct?

Thanks again.

Posted By: dualsport
Date Posted: April 22, 2007 at 8:06 AM

This should be all you have to do-
https://img293.imageshack.us/img293/3449/aircompressorcntldx0.jpg

diagram

Posted By: iblis
Date Posted: April 23, 2007 at 5:27 AM

Thanks dualsport, you've been a great help!

Posted By: hotwaterwizard
Date Posted: April 23, 2007 at 7:39 AM

A solenoid would be better!

How does the tank fill up?

Is it an On-Demand Aircompressor?

If it has a small tank, then it needs power to refill for the next Honk.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: dualsport
Date Posted: April 23, 2007 at 8:05 AM

You're thinking of those real air horn setups, I don't think this is one of those big rig air horn setups with a separate tank; the compressor only pumps when it's honkin'.

It's be fun to get one of those real air horn setups with the 26" trumpets, but I'm not dedicated enough to figure out how to get it mounted into my car- https://hornblasters.com/

Posted By: hotwaterwizard
Date Posted: April 23, 2007 at 8:18 AM

The reason I rthought about that is I just helped my boss figure out the Big Rigg type on his truck along with a Siren that I repaired for him.

posted_image

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: iblis
Date Posted: April 23, 2007 at 8:49 AM

Hi hotwaterwizard. The horn is a Stebel Nautilus https://www.stebel.it/stebel/index.htm. There is no tank as dualsport says. Sorry I should have been clearer about all that at the start posted_image