I am adding an air horn to my truck with an On-Off-On toggle to use so I can use either the air horn or the OEM horn. I was just thinking about it though, and my alarm is tied into my horn.

Would I tap the switch into the horn wire (Dark Blue Wire - Neg. when horn button is pushed) before the point that the alarm is tied into it, or after as I want the alarm to still use the OEM horns, rather than the air horns when it goes off, but want the steering wheel horn button to work the air horn when pushed if the toggle is set to the air horn.

Thanks.

 

It wouldn't matter where you tap in, if the air horn goes off with the steering wheel button pressed it's going to sound when the alarm triggers regardless. If you have if physically removed with the system with a toggle switch then it won't sound with the alarm.

Your best bet is to use a dual relay setup, one to supply power to the horns when the truck is running and the other to provide a ground when the steering wheel button is pressed making the horns sound.

 

I tied the relay in before (closer to the steering wheel) the point where the alarm is spliced into the horn and it works just as I wanted it to. OEM horn sounds for alarm, regardless of what position the toggle switch is in (Air Horn, Off, OEM Horn).

 

This is a another mod for me...how did you all decide on which air horn to use...I upgrade to the hella horns and used those two and my stock 2 and still not loud enough

 

That's why you have to use 2 relays. Basic electronics.

 

No I did not, it works exactly how I wanted it to with the one relay.

Maybe you misinterpretted what I was asking.

 

Let me see if I can clear this up some. You have one relay right now providing power to the air compressor. Ignore that one all together.

You already added a second relay to the horn button that provides a ground to activate the air horns.

Now from what I am understanding you don't want the air horn to activate when the alarm chirps.

What you want then is a relay on both the power and ground wires going to the air horn solenoid.

Add another relay with 12v power to the solenoid valve when the truck is running. Use a "switched" wire in the fuse box such as the radio wire to provide the "trigger" to this relay.

Now what will happen is this...

When the truck is off the air horns will be dead period. The alarm can chirp and go off but the air horns will still be dead.

When the truck is running, the air horns will be active. Then when you punch the steering wheel the air horns will sound.

Hope that helps. You could still get more creative and make the horns active after you arm the alarm but that gets a bit more complicated.

 

The one relay that I have is for powering the compressor.

The blue wire that leads from the steering wheels horn button to the horns was cut and then a toggle (on-off-on) was added. One on is for the air horns and one is for the OEM horn.

The alarm system is tied into this blue wire after the toggle so when the alarm system sends a pulse to the OEM horn (regardless of what position the toggle is in or if the truck is running or anything else) as it is connected after the toggle.

The way that I did it allows the air horn to be active when the steering wheel button is pushed when the toggle is set for air horns (regardless if the truck is running or not). The steering wheel button activates the OEM horm when it is set to the OEM horn position and nothing when the toggle is in the off position. Now, regardless of what position (Air horn, Off, or OEM horn) the toggle switch is in, the alarm ONLY uses the OEM horn as I do not want the air horns to go off with the alarm as it will be havoc on the compressor going on and off in pulses. The toggle is isolated BEFORE the alarm system is connected to the OEM horn so the alarm system sends the pulse to the OEM horn no matter what.