Horns / Wiring

Noseoil

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Looking for a convenient location to tap into a signal from the factory horn to do an aftermarket horn set.

There's no room to reach it inside the fender well, so it's a no-go there. Does anyone know the easiest place to tap into the relay panel or fuse panel to pull the signal for the new horn relay? A wire with the correct signal will do (bundle, wire color, location), but I don't want to start butchering things on a new truck. Thanks...
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Jfleming

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It depends on how you want to wire your supplemental horn relay. The original Ford wiring sends a ground signal to the Body Control Module (BCM) when you press the horn button. The BCM then sends a ground signal to the Horn Relay. The Horn Relay then sends a 12v signal to the horn.

The output ground signal from the BCM is in the cab next to the steering wheel (Connector C2280C). The horn relay is in the Battery Junction Box (BJB) (Located under the hood next to drivers fender, Connector C1035A). Depending on what you want to do, it looks like either of these could possibly work.

The attached schematic shows the overall layout, wire colors, connector numbers and pins, etc.

If you need more detail let me know.

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Noseoil

Noseoil

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J, thanks for this info. I'm planning on putting the relay in front near the battery location. I'll be using a 4 pin 30A relay & feeding 2 small high-output horns which mount in the grill area. There's a cross-bar with two slots below the grill, which will accept the horns without any modification, so it's a question of getting the signal & feeding the relay correctly.

I'm leaving the original horns in place, so the CRH02 Bu-Wh wire might be the best choice to feed a signal to the relay, hmmm. This should feed a + signal to the relay when the horn button is pushed, correct?

Otherwise, I can run a completely isolated horn button to the dash & have a second horn button for those annoying times when people need a bit more horn to move or react.
 

Jfleming

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Hello,

The Blue/White wire (CRH02) sends a ground (negative) signal to the coil of the horn relay. The positive side of the coil is fed with 12v positive at all times, and the circuit is completed by sending a ground (negative) signal when the horn button is pressed.

There is no reason that you couldn't wire in your second relay to work the same way.

Thanks,
 

Msfitoy

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Which wire connects the horn switch to the relay? Where can I find this wire physically? Thanks!
 


DrewKD88

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What Horns are you guys going with? I want to upgrade mine as it sounds like it's water logged now. I upgrade the horns on my motorcycles almost immediately after purchasing the bike. It's a must. I've used Hella, PIAA and Stebl. I'm looking for dual tones. Any recommendations?

Thanks!
 

CoMtnRanger

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It depends on how you want to wire your supplemental horn relay. The original Ford wiring sends a ground signal to the Body Control Module (BCM) when you press the horn button. The BCM then sends a ground signal to the Horn Relay. The Horn Relay then sends a 12v signal to the horn.

The output ground signal from the BCM is in the cab next to the steering wheel (Connector C2280C). The horn relay is in the Battery Junction Box (BJB) (Located under the hood next to drivers fender, Connector C1035A). Depending on what you want to do, it looks like either of these could possibly work.

The attached schematic shows the overall layout, wire colors, connector numbers and pins, etc.

If you need more detail let me know.

1.JPG
Hi, electrical engineer here. A simple way I went about horn replacement vs aux horn, is to remove F48 and replace it with a micro2 fuse tap, didn't populate the bottom fuse (effectively removing ability for power to flow to yel/red to factory horn), and instead used the top slot in the fuse tap with an appropriate fuse for the replacement horn, with the tap wire going to the hot side of the replacement horn. Now the steering wheel horn switch is simply driving a different horn.
 

Msfitoy

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What Horns are you guys going with? I want to upgrade mine as it sounds like it's water logged now. I upgrade the horns on my motorcycles almost immediately after purchasing the bike. It's a must. I've used Hella, PIAA and Stebl. I'm looking for dual tones. Any recommendations?

Thanks!
I have a 100 watt cop horn and it's loud as you'd expect...but the switch is not easy to reach in a panic so I'm looking to wire it up to the horn pad...
 

Msfitoy

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Hi, electrical engineer here. A simple way I went about horn replacement vs aux horn, is to remove F48 and replace it with a micro2 fuse tap, didn't populate the bottom fuse (effectively removing ability for power to flow to yel/red to factory horn), and instead used the top slot in the fuse tap with an appropriate fuse for the replacement horn, with the tap wire going to the hot side of the replacement horn. Now the steering wheel horn switch is simply driving a different horn.
Thanks for the tip Gregg...can you elaborate on "didn't populate the bottom fuse (effectively removing ability for power to flow to yel/red to factory horn), and instead used the top slot in the fuse tap with an appropriate fuse for the replacement horn"?
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