Long range plan is to use a (modified) LE siren (or system) in place of the horn on my Ex. (A horn sounding in a parking lot is just another horn. I plan to have something unique so I will KNOW it's my truck!)

Looking at the Anti-Theft system diagram in the OEM wiring manual (Pg 112-1), I do not see the horn in the system. I checked the Horn/Cigar Lighter diagram (Pg 44-1), and did not see where the Anti-Theft system tapped into it.

Any learned persons know which wiring diagram details the Anti-Theft System with the horn?

/r,

 

Search Wiring Diagrams

 

i have an aftermarket (Viper) 2 way alarm on my f350 (my excursion is stock for now), and i had the stock viper siren installed, as well as the horn honks with the siren, so its pretty loud, but i plan to add a home security siren with a relay (LOUD) under the truck.

 

I wired my air horns into the stock horn, it certainly gets your attention

 

The "Anti-Theft System" is the PATS system, it's not an alarm. PATS deters drive-away vehicle theft only.

 

So the PATS doesn't honk the horn or flash the lights in the case of a break in?

 

No, all it does is make sure the right key(s) is/are being used to start the vehicle.

 

Did you not read my previous post (or your owner's manual)?

 

So, when I hit the panic button I can't expect horn and lights? To clarify what I hope for, a unique sounding alarm whenever the system is activated.

The question remains as to how the horn is included in the system.

/r,

 

This is my understanding as well.

 

I never bothered looking at that part of the manual.I read your post and was just in
dis belief that in what I was reading. I have never given much faith in alarm systems as I had 1 with Viper and 1 with Carbine (if I remember that right) that were still broke into and 1 was stolen. But they do have their valuable points also

 

Sure you can, but that's part of the RKE sub-system, not PATS.

There is no factory electronic perimeter security system for the Exc except rolling up the windows and locking the doors. Anything other than that, you have to add it on yourself.

 

The panic button/horn/light (if you have it) is a separate system than the PATS. PATS is pretty much "key recognition" only.

The "P" in PATS stands for passive, meaning no owner input other than putting the key in the ignition. Pushing a button to make things happen would be "active."

 

From what I'm understanding here, all you're looking to do is add in an aftermarket horn/siren to the existing system? If that's the case why not just run a jump lead from the existing horn to trip a relay that powers the auxiliary add-on?

Unless you're trying to incorporate it so it ONLY goes off with the alarm system. That will require some extensive programming knowledge so it knows which horn to trip when.

Simple version IMO would be to wire a switch in to the ground for the aforementioned relay (I'm a fan of ground wires to in-cab switches over hot wires), that way when you park you can just flip the switch. With the switch not engaged, the relay won't ground and the siren won't go off when you have to honk at some nimrod driver.

 

By wiring the relay such that the coil was energized by a key-on powered circuit you could make the "switch" automatic, it would be horn with key-on, air-horn/siren with key-off.

I like your idea of switching the ground circuit, although it makes it a bit more dangerous for folks that think with the switch off the power leg is dead.