relay for air horn

Printed From: the12volt.com
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=31676
Printed Date: August 25, 2025 at 12:58 PM

Topic: relay for air horn

Posted By: modmastermitch
Subject: relay for air horn
Date Posted: May 06, 2004 at 12:45 AM

ok, well iv bought musical air horns and im readdy to fit em. the only thing is, the instructions are rubbish! i have a relay with 4 pins, now ive never used a relay before, ive tried to learn but reading is not as good a tool as using it and applying my knowledge,

so.... i need to know what size cables to wire from the relay to the compresser, and also where the other pins all go to!

help would be appreciated!

*mitch*

Replies:

Posted By: underESTimated
Date Posted: May 23, 2004 at 12:45 PM

modmastermitch wrote:

ok, well iv bought musical air horns and im readdy to fit em. the only thing is, the instructions are rubbish! i have a relay with 4 pins, now ive never used a relay before, ive tried to learn but reading is not as good a tool as using it and applying my knowledge,
so.... i need to know what size cables to wire from the relay to the compresser, and also where the other pins all go to!

help would be appreciated!

*mitch*

I used 16-18gauge wires.

I initially wired it up, without the relay. But blew a fuse for my brake lights.

No more of that. posted_image

I'm just lost for the relay hook up itself.

I have a 5 connector relay using a 30amp.

Posts are like this:
85

87a

Now, how would I wire this up so I dont blow anymore fuses.

Thanx in advance, and this is really the best informative site I've found. :)

Posted By: modmastermitch
Date Posted: May 23, 2004 at 3:31 PM

iv solved my problem,

pin 30 - use 30 amp wire with an inline fuse and hook up to + battery

pin 87 - use 30 amp wire and hook up to + on compresser

connect - on compressor to earth

pin 86 - connect this to a good earth point

pin 85 will go to a switch or the + wire of your original horn, id use a separate switch for this for legal/safety reasons.

and thats it, i didnt have a clue what to do until i9 tried it, iv now wired sevaral relays up to different things!

*mitch*

Posted By: underESTimated
Date Posted: May 23, 2004 at 3:55 PM

Thanx Mitch for both reply's and PM ;)