VW New Beetle remote lock/unlock

I need some help in figuring out a problem with remote door locking/unlocking on VW New beetles.

I've built a remote-access system that lets members access a fleet of cars with a security badge (prox card). My system connects to the yellow/blue (lock & arm) and YELLOW /GREEN (unlock & disarm) wires of the driver's side door control module in the VW New Beetle, and sends out a negative 0.6 second pulse on these wires to lock & unlock the driver's side door. The system has been installed in dozens of vehicles over the past year.

The problem is that sometimes, a car will not lock (or unlock) the door, but it can still unlock (or lock) the door. In other words, the user isn't able to either lock or unlock the car no matter how many times they try (the system alternates locking & unlocking the door each time it reads a valid badge). The problem seems to appear for a few minutes on certain cars, but then seems to clear up. I have not been able to duplicate the problem, so I'm wondering if my outputs are right on the edge of  not being accpeted by the VW module.

Does anyone know of the specs/timing for the lock & unlock pulses for newer VW systems? (I've seen notes that VWs need a double-pulse to unlock, but that seems to be to unlock all doors) Any other ideas as to why the lock or unlock signals might not work?

Thanks in advance!

Hi optodata, in the '98 and up Beetles, you want to send a double (-) pulse to the the unlock lead to disarm it. The unlock lead is WHITE/ Green or WHITE/ Light Green in the driver's door.

the12volt

the12volt - Thanks for the quick reply!

I've checked the wires I'm connected to with both a meter and oscilloscope when I turn the door lock with the master key. There is no double pulse and the wire stays grounded for as long as the key is held in the locked or unlocked position. There is no controlled pulsing on either of these lines, that's why I don't think the double pulse is the problem. Is there something I'm missing?

You mentioned a different unlock wire (WHITE/ green) inside the driver's door. (I found all my info from the "Official Factory Repair Manual" for the '98-'00 New Beetle CD-ROM from Bentley Publishers). The wire you've mentioned is only on vehicles with power windows. It runs between the door locking actuator and Door Control Module, which doesn't exist on cars with hand cranks.

I'm using the wire that connects to pin 6 on the 24-pin gray connector to the Comfort System Central Control Module under the dash.  I can defintely see the Y/Gn line get pulled to ground when the master key in the door lock is turned, so i know it's the right line. I guess I can try the double pulse and see what happens. Do you have any idea of how long the pulses should be, and how far apart I should space them?

Thanks again!

Hi optodata, you're welcome....if the double pulse does not solve your problem, try looking for a  WHITE/ Blue wire in the key cyclinder harness, single pulse to ground for unlock or a *Violet / YELLOW in the driver's door for the driver's door unlock (*will require adding a relay).

the12volt