I posted this in the electronics section but it didn't even get a single view. I'm trying to get this done this weekend so I was wondering if anyone who knows, anyone who put in an aftermarket alarm, could help me out with your experience:

I know others have installed aftermarket security into their C5's so I know there must be solutions to these two potential problems I've found

1: the factory alarm arms when you lock the doors, so the aftermarket alarm will arm both (not a bad thing) but when the factory alarm is armed turning on the parking lights alone will set it off, the aftermarket alarm could trigger the factory alarm while flashing the lights etc. what can I do about this?

2: when you hit the unlock button to unlock the doors while the factory alarm is armed, that will set the factory alarm off by default. this is good for factory security, but the aftermarket alarm need to unlock the doors. now, it will be connected to the factory alarm turn off circuit (same thing that disarms the alarm when you use the key in the door) but the factory alarm may cause the horn to beep for a second every time I disarm. of course I don't want this to happen. maybe the real system will be fast enough this won't happen? but for some reason I think this may be something I have to deal with.

please let me know if anyone has discovered solutions to these possible problems. are there any other C5 issues I should be aware of?

 

actually looks like the factory alarm only arms when hitting the lock button while the door is open. if its closed the alarm does not arm at all. I guess that makes sense, you wouldn't want it to arm if you are sitting in the car.

I wonder if that makes the solution easier?