Car Alarms: 1999-1/2 Jetta Alarm, keyless entry system, door latch

Question
The alarm will not disarm when I unlock the car with a key. Is there another way
to disarm the alarm so that the car will start? Dealer says possible fault is door
latch mechanism ($180 + installation labor). Is the an alternative fix like an
aftermarket part, etc.?  

Answer
The DEI sheet says that the factory alarm arms and disarms with lock and unlock.  If it is indeed the factory alarm, unlocking the door with the key should take care of it.  In the driver's door is a green/red wire at the module.  This wire is the unlock wire, it is a negative trigger.  This wire requires a double pulse to unlock (and should in turn disarm the alarm as well).  I would suggest to try and hook a jumper to this wire and tap it to ground twice, this should unlock and disarm the alarm.


The problem is that if it does work you would need to hook something more permanent to this wire, you could pick up an aftermarket keyless entry system and hook it up.  Most aftermarket systems offer a double unlock pulse output and reasonably inexpensive (should be no more than $50).

Hope this helps.