Installing a electric air horn

[druganjk@gmail.com]

Hi I bought a sound original compact twin air horn to replace my factory horn. I received the horn and a 4 pin relay pictures attached. My question is do I have to use the relay or do I already have a horn relay and 2 is this just as simple as pulling out one plug / relay and plugging in the new one or will I have to do some wiring.
Thanks
John

[EA37TS]

What do the instructions say?

Chassis manual should tell you if there is a horn relay for the factory setup.

[Yvonnemarc]

I put a WOLO Big Bad Max air horn on my truck. I used the relay already installed as I replaced my OEM horn with the existing wiring. If you wire this independent of the stock horn you’ll need to use the relay.

[16ACE27]

When I installed air horns on my coach I tapped into the OEM horn wiring for the trigger signal AND used the relay for the air horns main power. This instituted a slight delay for the air horns but the OEM horns worked as before. This allows me to do short toots as required for signaling but if I lay on the horn button the air horns kick in for the blast that is sometimes needed for oblivious drivers.

[ducksface]

Originally Posted by 16ACE27

When I installed air horns on my coach I tapped into the OEM horn wiring for the trigger signal AND used the relay for the air horns main power. This instituted a slight delay for the air horns but the OEM horns worked as before. This allows me to do short toots as required for signaling but if I lay on the horn button the air horns kick in for the blast that is sometimes needed for oblivious drivers.

That's exactly the way to do it.
And
It's also how you do auxillary lighting. Trigger is the stock light and aux has its own power.

Now a slight hijack:
Years ago I was admonished, but not ticketed, by a California cop due to my horn modification.
'horns are regulated by dB, go home and unplug that thing'

I went home, read up, and yes, horn dB was regulated by vehicle type.
I also read of a lawsuit where someone was startled by an 3xtra loud horn, over corrected, wrecked and won against the honker.
This story was all too many years ago to have any reasonable validity now what with the multiple front white light laws being ignored, the windshield height minimums being ignored etc.
Jc Whitney and all others used to have horn disclaimers in their ads.

Any input as to legality?

[EA37TS]

Listing of state laws.

The majority seem top prohibit the installation of supplement horns or ones that are not stock to the vehicle unless it is for an anti-theft alarm and disabled while driving.

https://hornblasters.com/pages/state-laws

[The_Breeze]

Originally Posted by EA37TS

Listing of state laws.

The majority seem top prohibit the installation of supplement horns or ones that are not stock to the vehicle unless it is for an anti-theft alarm and disabled while driving.

https://hornblasters.com/pages/state-laws

Beginning to see a lot of that with jake brakes too, particularly within city limits and seems to be expanding to rural areas. Some guys use it to announce they're presence/arrival and it's just plain rude.

[EA37TS]

Originally Posted by The_Breeze

Beginning to see a lot of that with jake brakes too, particularly within city limits and seems to be expanding to rural areas. Some guys use it to announce they're presence/arrival and it's just plain rude.

During our last trip to TN and also on our trip to IN in August, I saw a number of signs along the road that said "No unapproved Exhaust Brakes". Now, what is an unapproved "Exhaust Brake"? My Exhaust Brake was installed by Cummins and Freightliner does that mean it is approved?

I agree in an urban area with a 25MPH speed limit I see no need for the exhaust brake. On a 2 lane state or US highway with a 55 or 60MPH speed limit, well that's another issue.

[16ACE27]

Originally Posted by EA37TS

Listing of state laws.

The majority seem top prohibit the installation of supplement horns or ones that are not stock to the vehicle unless it is for an anti-theft alarm and disabled while driving.

https://hornblasters.com/pages/state-laws

I didn't look at every state but the pattern I see says two things:

1 - No vehicle may be equipped with, nor may a person use, a siren, whistle, or bell, except as otherwise permitted - in other words; you can't sound like an emergency vehicle.
2 - Any horn or other warning device shall not emit an unreasonably loud or harsh sound - Any statute that is written with a subjective test is next to worthless. What's "unreasonably loud or harsh" to one person is normal for another person. There has to be an objective standard for it to be enforceable in a true court.

It;s interesting Virginia's statute says: "It shall be unlawful for any vehicle operated on a public highway to be equipped with any warning device that is not of a type that has been approved by the Superintendent".
Superintendent of what?

[Yvonnemarc]

It’s all very vague. Leaves judgement to LE. That said I did note there is very little on db level. This site must have old or non specific information. My state actually has a section on horns, db, etc. calls out train horns mounted on vehicles are strictly prohibited. Your state likely has very specific info on this subject.