stock alarm goes off randomly?

I did this about 2 years ago, http://www.customtacos.com/tech.old/index.php?article=12

It is a "free alarm mod" that I am sure some of you have heard of. Anyways, last year around december I had an autopage RF-425 installed and I love it (it sounds with a siren), it is a great 2-way alarm. My problem now is the stock alarm (the way to activate it is to disconnect the wire under the dash) goes off randomly, in the middle of the day, and it goes off twice every time. I hear it go off, i use the autopage remote and unlock the doors, it goes off, i lock the doors and i get the chirp. Then about 5 minutes later the horn is honking and the lights are flashing again. then i unlock it and lock it again and it is fine until the next day, these are all at random times and it all started about 4 days ago. I think i can totally disable the stock alarm (horn) if i reconnect the two wires that i disconnected to get the "free alarm mod" but the problem is, when i had the aftermarket autopage alarm installed the dealer wrapped up all the wires and i can only locate the female end of the harness. Where would the other end be?!?!?!? I have looked for hours and not found it lol! Can anyone direct me in another way to disable the horn alarm?!?!?! Or a starting point for for the other end of the wiring harness? Thank you very much for your help, and as of now i have removed the horn fuse for the night.

 

Edit: When i unlock the truck after the horn alarm has sounded it makes the beep noise like when you try to lock it with the stock key fob and the doors are open. its only after the alarm has sounded

 

The stupid alarm guy that installed my real alarm tucked the other end of the wire in with their wires and some electrical tape, so i found it thanks to the pictures on the original write up, thanks.