He was taking the trigger from the solenoid that unlocks the door. Thats what I was alliuding to first, but the BCM would be neater to tap into as you dont have to go to the door. Oooh, another idea, in the boot area there is a ruddy big loom powering the lights and most importantly the boot lock soleniod. Might be worth tracing that as it will have to come nicely past the rear cubby area. Means no chasing wires up to the front of the car
The only thing that might confuse it is when you do a double unlock to unlock the passenger side. Hopefully you do it quick enough, its still in boot up lockout on the PSU so it wont do anything with the signal, but if you dont get the IGN on before boot up lockup timer runs out, it might try and shut it down again.