Hi guys i joined this forum so i could let you you know how to fix your issue of it no longer working after 15 seconds.
My car is a 2001 Porsche 996 911 3.4 but this will also work for the 986 boxster. Please note my car RHD so my ecu is under my the passenger seat (left hand side of the car) Im unsure if its also on the same side on a US car
The ecu has two main connecter plugs. One plug has inputs into the ECU and the other plug is outputs. The problem you guys are having is that you have wired into the ecu input wires not output.
I sorted my issue a couple of months ago but it has taken my account a while to activate so i will do my best to remember.
Right first thing you need to do is read the instructions of your aftermarket alarm. You will be wiring it as Single point locking NOT negative ground locking.
This means you will be wiring it as if you are wiring it to an actuator that will reverse the polarity of the wires when you press lock or unlock.
The wires you are looking for go into the rearmost plug of your ecu.
If you look at a porsche wiring diagram for your door lock, you are looking for the two wires that run the central locking motor in the lock. Mine were terminal A1 (Blue/Yellow) and A2 (Green/Red). Both front door locks are linked to the same two wires where they go into the ecu.
If you look at the rearmost plug on your ecu you will see these two wires (Green/Red and Blue/Yellow). Please note: there are another pair of wires that are the same color but with a colour band round them It is NOT the banded wires.
You need to cut the the two wires and then join them to your 3rd party alarm. You will be using the loom end of the wires you have cut NOT the end where it goes into the ecu.
I have done my best to explain this. Let me know if i can be any more help
