1998 pathfinder, horn wiring

Is anybody here familiar with how the horns are wired on a 1998 Pathfinder?  Basically what I need to know is which wires are connected to the horn switch.  I'm trying to install an aftermarket horn for my dad (yes tacky, i know).  It has a box that controls the output to the horns for different sounds.

I've taken the following wiring info off of  www.directechs.com website:

DIRECTWIRE™ WIRING INFORMATION - NISSAN / PATHFINDER / 1998 / Remote Start

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12volts  WHITE/ purple    +   ignition harness 

Starter  BLACK / YELLOW    +   ignition harness  Second Starter  RED / blue    +   ignition harness  Ignition  BLACK/ white    +   ignition harness  Second Ignition          Third Ignition          Accessory  WHITE/ blue    +   ignition harness  Second Accessory  RED / yellow    +   ignition harness  Keysense          Power Lock  lt GREEN/ red    -   keyless entry module  Notes: Keyless entry module is located under drivers side of dash. Power Unlock  brown    -   keyless entry module  Notes: Keyless entry module is located under drivers side of dash. Lock Motor  blue      keyless entry module  Notes: Keyless entry module is located under drivers side of dash. Unlock Motor  WHITE/ purple      keyless entry module  Notes: Keyless entry module is located under drivers side of dash. Parking Lights+  pink/blue      at steering column  Parking Lights-          Hazards          Turn Signal(L)          Turn Signal(R)          Reverse Light          Door Trigger  RED / black    -   drivers kick panel  Dome Supervision          Trunk/Hatch Pin  tied in with doors        Hood Pin          Trunk/Hatch Release          Power Sliding Door          Factory Alarm Arm  yellow    -   keyless entry module  Notes: Keyless entry module is located under drivers side of dash. Factory Alarm Disarm  light green    -   keyless entry module  Notes: Keyless entry module is located under drivers side of dash. Disarm No Unlock          Tachometer  blue    ac  at distributor  Wait to start          Brake Wire  GREEN/ YELLOW    +   at switch  Parking Brake          Horn Trigger  lt GREEN/ black    -   steering columnMemory Seat 1          Memory Seat 2          Memory Seat 3           Interface Module: Category:Immobilizer Bypass  Required:No Type:N/A Part #: N/A Notes:   Smart Starter Kill Relays: Not Available  I needed to tap the wire that goes to the horn switch and route the signal to the aftermarket horn unit, so I tapped into the Lt GREEN/ black wire.  This was wrong after almost having a heart-attack.  It activated the horns and they stayed on non-stop.

So now I'm stuck and would like to know if you guys know which wire I should tap.

Any help would be greatly appreciated!

-Ian