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I'm working on an air horn implementation and am all finished except for the electrical connections. After reading a few of the posts related to the OEM horns and/or the wires involved, I think I'm more confused than before I started on this project. Can anyone provide me with a definitive description of the wire or wires involved...or an answer of how to access the wires at or near the horns without having to remove the fender/shield? I'd like to be able to switch between the OEM horns and the air horn, but still have them work via the steering wheel horn switch. Thanks in advance.
After fighting with stuck bolts, and fender liners that simply don't flex in the cold, I finally decided to give up on accessing the OEM horns and wire everything directly under the dash.
First, here's the setup I went with...
However, I swapped out the puny 1/4-inch plastic tube (about equivalent to a really long straw) it came with to 3/8-inch 300 PSI tubing (seen in the 3rd picture below).
I mounted the compressor and tank at the front of the bed of the truck. I backed out one of the bed bolts, inserted a 12-inch long, 1/8-inch thick, L-bracket on which to mount the compressor and tank, and re-fastened the bolt. Then I used 10-inch hose clamps to strap around the L-bracket and tank to secure the tank to the bed.
I mounted the dual trumpets between the grill and radiator, bolted through the fiberglass pillar, reinforced with metal brackets.
Thanx to a post by Mr. Sandman, I utilized the blue wire...
...as the ground for the air horn trumpets. In combination with the pass-through wires, I connected to an always-on 15-amp circuit...
...for the power for the trumpets and to a 30-amp switched circuit...
...for the compressor.
Now, when I honk the horn, I get the dual electric OEM horns sounding and the dual air trumpets simultaneously. In addition, when I lock the rig, the electric burst to the dual eletric OEM horns is short enough that it doesn't sound the air horns...only when the panic alarm sounds. It all turned out great (although took quite a bit of time to snake the air hose and wires to and fro, but well worth it in the end. Holy ~!@#$, is this thing loud! I'll post pictures of the install later today or tomorrow and, if I'm able, perhaps a recording of the sound.
This forum is such an incredible wealth of information and this project would've taken me so much longer had I not had access to the forums!
Okay, for a quick update, one morning last week, I went out to start my truck and instead of the truck starting, the ignition fuse blew and the OEM horn sounded and didn't stop until I pulled the fuse. Jeez.
Long story short, I decided to completely rewire everything.
The compressor is grounded to one of the bed bolts.
Upfitter switch #1 connects to the red firewall pass-through wires, which is power for the compressor.
Upfitter switch #4 connects to the white firewall pass-through wire, which is power for the air horns.
Now, I attempted to connect the ground from the air horn to the blue wire for the OEM horn, but when I do so, the OEM horn sounds constantly...whether or not upfitter switch #4 is on.
So, at this point, I'm not sure how to connect the final ground wire for the air horn. My goal was to be able to have the OEM horn work as normal and for the air horn to work together with the OEM horn only if upfitter switch #4 is on.
Am I missing something?
I don't know why this worked from the get-go, but then failed for whatever reason.
Any suggestions for how to get this to work the way I described?
You are working on the 06?
The diagram I am looking at shows the horn gets it power from the CJB
by way of a Yellow/Light Green wire then the ground side is Black.
Now for the control side you have the relay controlled by Dark Blue wire
that leads to the clock spring, then the switch and back out to ground.
If you ground the Dark Blue wire it will honk the horn because it gives
a ground to the relay.
I'll attach the PDF for you to look at. This is from the Ford Work Shop Manual.
Look at page 44-1
The airbag sliding contact in this case is the clock spring circuit for the horn
in both cases. The part called "Steering Wheel Speed control switch is
the horn switch.
Hope this helps you out. If you need more info just ask or you can PM me.
Okay, I see the YE/LG connector in the schematic, but that is a power line, not a ground, right? So, if I have the power to the air horn connected to upfitter switch #4, how can I connect the ground to the air horn so that it will sound (along with the OEM horn) when I press the horn on the steering wheel, but only when upfitter switch is on, so that only the OEM horn will sound if the switch is off? Can I do that with only my remaining air horn ground wire to connect or do I have to re-wire again?
Let me do a little thinking about it and I'll try and
get you something drawn up.
How are you controlling the compressor ?
Does the horn use a air solenoid?
You want to be able to enable and disable just the air horn
and have the factory one all the time?
Do you want to use upfitter switch #4 as the on and off control?
Sean
Just an FYI Switches
Circuit
Color
Fuse
Aux 1
CAC05
Yellow
30 Amp
Aux 2
CAC06
Green/Brown
30 Amp
Aux 3
CAC07
Violet/Green
10 Amp
Aux 4
CAC08
Brown
15 Amp
Power for compressor runs off upfitter switch #1.
Compressor is grounded in truck bed.
Power for air horn runs off upfitter switch #4.
Air horn is not yet grounded.
Yes, the air horn does have solenoid.
Yes, I want to be able to enable/disable just the air horn and have the factory horn work all the time.
Yes, I'd like to use an upfitter switch as the on/off control for the air horn. I suppose I could use the same switch for the compressor and the air horn...it doesn't really matter as long as I have the ability to disable the air horn and still have the factory horn work.
Is the compressor big enough that you would be able
to run any air tools or inflate a tire? That would be an
excellent reason for 2 switches and not one.
The compressor I have now is probably not going to cut it for that as it's only 2.5 gallons. However, there's no reason I couldn't swap it out in the future. So, with that in mind, would I still need a separate switch? A 30A connection isn't enough for the compressor and the horn?
If you look at the Yellow/Light Green wire that hooks to the horn
at connector C131 pin #2. I would add a relay at that point. No need to
cut the line but just tap off to supply power to the relay coil and the
other side of the coil will need a ground. Then you have a set of
contacts that will close any time you honk the horn. You can then
take switched contacts of the "new" relay and use that to control
the power to the air horn that is switched from upfitter switch #4.
All done.
Sorry, but I'm not sure I understand. I think I need to simply ground the air horn, then re-wire the power for the air horn to the YE/LG wire, but I don't understand the relay and the additional ground. And, how would my connection to the upfitter switch #4 come into play? Doesn't the upfitter switch already have power to it? Apologies for the confusion.
12-10-2014, 04:38 PM
