I am trying to wire a relay into my existing horn circuit so that I can selectively choose between activating my "sick goat" stock horn or my fire truck air horns using the steering wheel.

I'm trying to track the horn wires into the bundle and then splice my relay into that line, but I keep losing the wire as there isn't much room forward of the ECU.

Does anyone know which of the 2 bundles, (located between the the ECU and the firewall) the upper or lower, that contains the horn wire? Or even what color it is?

TIA,

 

is easily located in 2 places:
HORN DARK GREEN/PURPLE (-)

@ HORN SWITCH or or INSTRUMENT CLUSTER, (BLACK, 20-PIN PLUG) PIN 10

...but not necessarily which wire bundle yet.

for those that may be interested, I found the data on a website selling automotive security systems.