Wiring Guide for Installing Dual Horns with 12V 40A Relay and 30A Fuse

Hello, I would like to install a separate horn in my car - I don`t want to resuscitate the old installation, something died - that`s why I want to install a new one.

For this purpose, I purchased a normally open button, a 12V40A relay and 2 horns.

There are a lot of diagrams for such relays on the Internet, but I can`t identify them with my situation - so I`m asking for help in solving my problem, which I would like to see illustrated or described in detail - regarding the picture I attached.

Oh, and what fuse should I use? 30A is enough?

https://obrazki.elektroda.pl/6628528000_1346780679.png

Dziarski Hank - unfortunately your description does not work, I connected everything correctly, I only had doubts whether the relay itself was functional, so I got another one, but without a positive result.

I am attaching a photo of the relays I have.

The diagram is definitely correct. You`re doing something wrong.

Well, that`s what I thought at first, but after checking it again, I got another relay and checked the whole thing again (from the efficiency of the horn itself to the normally open button). The problem is not in my design - maybe both relays are on the left side?

kedly wrote:

The problem is not in my design - maybe both relays are on the left side?

Only you know that.
Connect the horns as shown in the drawing, and independently supply power to the coil and check if they start. If so, you have a problem in the control circuit. Pull out the relay and supply power directly to the horns with some wire. If they don`t move, you have a problem in the electrical circuit. It`s a trivial diagnosis!

It just dawned on me, I went to the car and it turned out that I`m a hammer, I forgot to put the fuse in the housing. Now everything is running smoothly. Thank you for your help!