94 Corrado alarm install with OE alarm

I want to install an alarm in my Corrado & keep the factory alarm working. I would like to have the aftermarket alarm lock the doors & arm the factory alarm. I would also like a secondary channel to close the windows & sunroof. I read in the archive that I access the lock & unlock signal with the RED / yellow and the RED / black, these would need a positive signal. How would I arm and disarm the factory, is this done through the central locking? How would I access the windows, the instructions are kind of vague in the archive. There are no window relays in the fuse panel, there is a window control unit in the rear quarter. I thought I would use the factory alarm to monitor the doors & signal the aftermarket alarm if any zones were broken. I wanted to minimize the amount of wiring in the car and thought that using the factory alarm & aftermarket one together would solve this. I was going to have the aftermarket alarm set off the factory alarm if the shock sensor goes off on it. I would like the windows & sunroof to be closed on a separate signal so I can leave them open a crack. I haven't purchased an alarm yet but I wanted to make sure I have all of the information incase the alarm needed any special features.

Thanks for any information, Dennis

Sorry, I've been posting in Corrado lists and I keep forgetting that it's a Volkswagen Corrado, my bad. Thanks for the information, I was wondering if you people could help me with arming the factory alarm as well using the aftermarket alarm. What wire would I have to slice into on my cars wiring to arm the factory alarm.

Thanks for the all of the help, Dennis

Thanks Jeff, that really helps me out. If I wanted to have the windows work on a secondary channel, what should I do. If I hold the key in the lock position, the windows and sunroof will close. If I buy an alarm and program it to use the lock signal when I press the secondary button on the remote, will I have any problems? I would think that I could just push and hold the secondary button until the windows were closed, does that make sense or are there any special features that I would need in the alarm? If that were the case, I could have the secondary button and the arm button go to the same relay. I would just splice the lock & unlock wires into seperate relays that would be triggered by the alarms signals. Thanks again for all of the help everybody, I think I have this figured out.

Dennis 

Ok, I went and did a search to see what a latched output is and I found one of Jeff's posts that explained it very well. I noticed that some people used a diode when interfacing with the cars wiring, is this something that should be used all of the time or just in some situations. In my car, I was going to have a lock and unlock relay. The lock relay would be used for two things, to lock the doors and arm the factory alarm with the main button on the remote and I was also going to use a secondary button to hold the lock relay to roll up my windows. So the alarm would have 2 wires going to this relay, should I use diodes to isolate the 2 circuits or would they be ok.

Thanks for the great information, Dennis 

OK, heres my follow up on this for anybody else that wanted to do this. The Corrado locks the doors & arms the factory alarm & raises the windows through the central locking. Hold the key in the lock position and everything is done. I just tapped into the passengers door lock harness where it exits the door. On my 94 Corrado there is nothing behind the passengers kick panel so that is where I mounted my control unit and thelock and unlock relay. The central locking system uses a 12 volt positive signal to activate it. The central locking uses a red / black wire for the lock and a red / yellow wire for unlock. If you send 12 volts positive to the red / black wire then the doors & factory alarm & window module will activate.  I used the factory alarm to monitor the doors & activate the starter kill. The horn on my car only makes noise when the alarm is triggered so I put a relay on it and when it goes off it will send a ground signal to the door pin switch on the aftermarket alarm and trigger it. If the shock sensor goes off on my aftermarket alarm then it will also send a ground signal to the door pin input on the factory alarm and trigger it. So both will go off at the same time and to dis-arm them you just click the remote and that will dis-arm the aftermarket alarm and the alarm also sends a 12 volt positive signal to the central locking and unlock the doors & dis-arm the factory alarm. If you want to roll the windows up, just send a 12 volt positive signal into the lock relay for the doors and that will roll the windows up. I used a couple of diodes on the lights because the factory alarm flashes the turn signals and not the marker lights. If I wired the single light flash to the turn signal wires coming out of the factory alarm then every time I use a turn signal both sides would flash. I ended up tapping into 5 wires on the car: lock and unlock in the central locking, left & right turn signal wires coming out of the factory alarm unit, horn signal coming out of the factory alarm, and the door pin signal going into the factory alarm. I ran a seperate power for the alarm control unit and another for the relays & central locking interface. I have tested it and it works really well, thanks for the help on making this work.

Dennis