After market car alarm issue

Hey all,

So I have a 2002 Tacoma S5 which came with an aftermarket car alarm. The alarm is an UltraStart 1256m. It's been a solid alarm and worked fine until the following issue arose:

I took apart my dash to install a new stereo+tablet. I noticed that when the dash came out, the control module (brains of the damn thing) disconnected from at least one wire. There were two other wires behind the dash exposed as well. Here is the deal

There is a blue/white wire coming out of the control module which is supposed to be connected to the horn wire. There is a green wire coming from up in the dash somewhere and a red wire from the dash also. The horn no longer beeps when I lock or unlock my truck via my remote and the alarm will no longer sound when I hold the lock button on the remote.

I'm going out now with my multimeter to try and figure a few more things out but I was wondering if anyone here knows what wire the blue/white one should be connected to in order to regain my horn honking when I lock/unlock.

I went ahead and capped each wire to prevent shorts in the mean time.

Here is a photo of the three original unconnected wires as well as a white/red one I found just tucked up in the dash:


Here is where the red one connects once I traced it back through the firewall:


Here is the wiring diagram I found for an 03 tacoma horn. It shows a green and red wire going to the horn switch. Perhaps both the loose green and red wire connect to the Blue/White wire from the head unit for the alarm system?
https://drive.google.com/file/d/0B8gddg29KYnPVEtjRXg4N2d3NzQ/edit?usp=sharing