wiring 4 tone gm horns in subaru

Hello,

Thanks for reading.

My goal is to install loud 4-tone (four horn) GM horns in my 2013 Subaru. I'll keep the pathetic OEM horn wired as is and add a momentary switch to control the 4-tones. This is exactly what I want to do.

I don't have a ton of experience with automotive wiring, so please be patient with my questions! Each of the four horns came with a connector with positive and negative leads. My research suggests that each of the positive leads needs to be connected to the battery. (To make this easier, I will be going straight to the battery and not messing with the OEM wiring.) Rather than have long runs from each horn to the positive terminal on the battery, is it advisable to run power to a bus bar (or two) and supply the power to the horns from the bus bar? Is this the appropriate use of a bus bar? Is there a better way to join four positive wires? I should mention that I hope to have two horns on one side of the vehicle and two on the other side.

How would you suggest grounding all four horns? Should I bring all four grounds to the negative battery terminal? To an intermediary bus bar? A better, less expensive idea?

I've included a photo of one of the connectors, the relay that came with the horns, one horn, and the instructions on how to wire to the relay (from the person who sold me the horns). Also, here is a schematic that FireEater on a Dodge Durango forum created when completing a similar install. I'm not sure why he used two relays.

Any help and suggestions welcome.


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2013 Subaru Outback Limited
2005 Toyota Sequoia

I doubt if one relay will power all 4 horns unless it was the original for the 4.
You will actually get far more volume from a set of twin air horns.
If you decide to go ahead, wire as follows.
You have to find your factory horn horn trigger that will be a thin red going from the horn push (steering column loom) to the existing horn relay, probably under the hood.
Join that wire to relay black with white stripe.
Red and tan or grey small wire join and fuse at 40 amps. From battery.
Green to each horn.
Black, each horn to ground, either at battery or local mounting bolt.
Bus bars? Why over complicate.


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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Thanks for the help!

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2013 Subaru Outback Limited
2005 Toyota Sequoia