Originally Posted by
onehundred80
The locking/unlocking system is not a normally open or normally closed system. Air pressure is used to open the locks and vacuum is used to lock them. A broken line will effectively keep the locks engaged or open depending on their position when the failure occurred.
If any clicking sound is coming from the latch area itself when the key fob lock and unlock buttons are pressed then I think that the lock mechanism itself has failed. No sound from this area would indicate to me that the air/vacuum hose has broken, in this case a hissing sound may be heard, possibly at the top of the hatch on the drivers side.
The following is from the shop manual page 8Q-47
VEHICLE LOCKING/UNLOCKING
To unlock, the Body Control Module is actuated by the SKREEM. The Body Control Module then sends the signal
to the Central Locking Pump/Security System Module (CLP/SSM) via the Controller Area Network (CAN) Bus. The
CLP/SSM pump motor starts running and supplies air pressure. The door lock actuators are pressurized. When a
pressure threshold is reached in the system, the pump is switched off by an internal pressure switch. The pressure
in the system is then released by the CLP/SSM and the unlocking operation is completed. The locking procedure is
accomplished in a fashion opposite to the unlocking operation. However, the next time the remote control button is
pressed, the CLP/SSM is also actuated by connecting it to ground by the second control lead on the SKREEM. The
direction of rotation for the CLP/SSM pump motor is reversed, thereby providing the vacuum required to lock. In
order to avoid unlocking the vehicle unintentionally, the vehicle is relocked by the CLP/SSM via the SKREEM.
Relocking is accomplished after unlocking with the remote control when: a door is not opened within 40 seconds,
the key is not inserted into the ignition lock, the interior power door lock switch is not actuated, only the liftgate is
opened after unlocking. The CLP/SSM reads the signals (door contacts, trunk lid, interior power door lock switch)
and actuates the power door lock actuators. The vehicle security alarm is also activated by the relocking function.
Just bought an 04 and your forum has been fantastic!
just wanted to say thanks Nd great job!