Horn Honk Operation

[JLandry]

So the other day while driving through the middle of nowhere I decided to try out honking the horn on our new truck... see how it sounded and all. While it worked, I was surprised by a noticeable delay between my pressing the steering wheel hub and the horn sounding. It seemed like the delay ranged from a fraction of a second to a full second. After years of near instantaneous reaction when pressing the horn button in prior vehicles I've owned, this new one is going to take some getting used to.

Then I read this in the factory service manual:

The vehicle operator can control typical horn system signaling through the horn switch contacts within the hub cavity of the steering wheel. When the Driver AirBag (DAB) trim cover in the center of the steering wheel is depressed, it provides a hard wired analog input to the Local Interface Network (LIN) slave node integral to the LIN module or the speed control switch pod in the right horizontal spoke of the steering wheel. The LIN slave node then sends an electronic horn switch status message to the LIN master node integral to the SAS. Then the SAS, which is also a gateway to the CAN data bus, relays an electronic horn request message to the BCM over the CAN data bus.

In addition, the RFHM sends electronic horn request messages to the BCM over the CAN data bus in response to inputs received from the Remote Keyless Entry (RKE) transmitter in vehicles without the optional Passive Entry Keyless Go (PEKG) system, or received from the FOB with Integrated Key (FOBIK) transmitter in vehicles with the PEKG system. Lastly, as the Vehicle Theft Security System (VTSS) controller, the BCM can activate the horn system based upon programming and both hard wired and electronic message inputs from the various VTSS components.​

Geez! With all these modules passing messages to each other before triggering the horn relays, NO WONDER there's a delay!

Things sure have changed.

John L.

 

[MJWenrich]

Good grief. Could they dumb that down a little so we can understand it? Oh wait. I asked my 13 year old grandson. He said we probably should not use it because the other driver might activate the **** module in their pants when the see the sight of a RAM in their rear view.

 

[JLandry]

Good grief. Could they dumb that down a little...

The factory service manual IS meant for your tech-savvy 13 year old grandson.

John L.

 

[PC12Driver]

Not many actual switches left in these trucks any more. Just network devices sending signals down the CAN bus pipeline to whatever controller needs it.

 

[JLandry]

Not many actual switches left in these trucks any more.

Drive by wire...

John L.

 

[BIGNASTY]

Would hate to honk the horn and have the airbags deploy!!! from mixed signals

 

[SnoKing]

Well John, that probably explains the throttle response delay on launch also. Read the section of what happens when one depresses the throttle pedal!!!!

Did someone say bumpy electronic road ahead? Was that Di? Chris

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