Wiring An Air Horn

[Opex]

i just bought a cheap air horn for the truck... but im not big on wiring... its a 2 horn 12v kit. i have a 2006 2500HD can anyone tell me how to install it... the diagram that came with it dont help me much

[Crawdaddy]

We could really use a lot more information before being able to really help. Is this an air horn with a built in air compressor or one that has an external air feed? No matter what, you will probably need a relay to supply power to the horns...

[Opex]

ya it came with a lil compressor

[Rumpamuro]

So this air horn was like a kit?
what exactly did it come with, any wires, relays, switches, check valves?

[Opex]

So this air horn was like a kit?
what exactly did it come with, any wires, relays, switches, check valves?


2 horns compressor relay and the hardwear... no wires

[Sooner]

I installed one when I was in high school (about 20 years ago). After installation, I asked my unsuspecting brother to check the oil for me. Right about the time he touched the dipstick, I nailed the horn. He slammed the top of his head into the hood and nearly wet his pants. I ended up locking myself in the car while he cooled down. But, he got even later. Anyway, here's what I'd do.

Disconnect the negative battery terminal. Find a suitable place to mount the air horns, compressor and relay. The horns should be louder if they are pointing downward and closer to the ground. You will need to buy electrical wire, splice connector and a fuse based upon the amperage of the compressor. Run a ground wire from the negative side of the relay coil to a suitable grounding location nearby. Splice into or reroute the oem horn power wire to the positive side of the relay coil (temporarily reconnect the negative battery terminal, have someone honk the horn and use a test light to determine the hot wire if necessary). With the negative battery terminal disconnected, connect the fuse to the positive battery terminal and run a power wire from the other side of the fuse to one of the relay contacts. Then run a wire from the other side of the relay contacts to the positive wire on the compressor. Finally, run the ground wire from the compressor to a suitable grounding location on the truck. Reconnect the negative battery terminal and test out the horn.

Enjoy.

[Opex]

ok thanks.... and wut gauge of wire should i be useing?

[bigrob1977]

8 to 10 gauge ought to do it. if the compressor draws alota power don't afraid to go to 4 gauge.

[Opex]

ok thanks... so i use 8-10 for the horns and wutnot and 4 for the compressor... and do i need to use one of the fuse things that u use for subs?

[Sooner]

ok thanks... so i use 8-10 for the horns and wutnot and 4 for the compressor... and do i need to use one of the fuse things that u use for subs?

I recommend using 18 Ga. from the oem horn to the relay coil and from the relay coil to ground. As for the wire from the battery to the relay contacts and to the compressor, reference this chart (http://www.mikenchell.com/forums/album_pic.php?pic_id=35343). You're going to have to read the instructions if it's not stamped on the compressor to determine the amperage draw and fuse size. That's not something you should guess at. I'd be surprised if you need anything larger than 12 Ga.

[Pete95Sierra]

i installed a similar horn in my truck pretty much the same way three years ago and still works great today

[bigrob1977]

oops i just wired one on my frieghtliner and my brain was still stuck in big truck mode. yes 18 should work fine.