Need a little help with central locking system . . .
 

yep, did a search, lots of good info, but couldn't find the help I needed. I have the Bentley manual, too.

Here's what's happening:

If I manually lock both doors (physically turn the interior lock buttons), the red light comes on on the central lock button. If I press the button, both doors will unlock. Also, if I unlock either the pass or driv door from the outside with the key, both locks open.

In other words, for UNlocking, it functions as it should.

But to lock, it doesn't function right. If I try to lock it from the outside, either pax or dr side, nothing. No sound, no action. If I manually lock either door from the inside, that door will lock, but the other side isn't triggered.

When I press the central lock button to lock it, nothing. No sound, no action.

I have taken both door panels off and looked for obvious broken parts, the wires all look fine, linkages and plastic pieces intact and fine.

The entire system isn't dead, since it works in the unlocking function.

My guess is it isn't anything in the doors, or the sensors/triggers on the handles. Because if it were, I should be able to still lock it by pressing the center console button, no? (Remember, I can UNlock it by pressing that button).

Any ideas?

On my system, the pax side wire was severed where the pistion connect to the locking mechanism. It is located near the lock itself. I recall it was a white wire loosely hanging there.

Mine would lock then unlock by itself as if I did not close the door, but I did.

I've check the wiring, physically it is all there and connected.

OK, here's a more specific question:

How does the central locking system know when the driver's door is open? What sensor/trigger does it use for that?

Sounds to me like a problem with the central locking control unit, located way deep in the back of the trunk on the right side and impossible to reach.

An easier thing to check, though less likely the culprit, is the central locking button harness connection behind the center console. There are two 2-pin connectors, one with yellow and blue wires, the other with grey and brown. Make sure the connections are tight and inserted correctly.

Probably the same way the interior lights know when the door is opened and closed - by the door switch, located in the front door jamb and covered by a rubber thingy.

I don't know that central locking attempts to discern whether the door is open or not. Opening the Drivers side door mechanically disables the lock mechanism in the Carreras (I believe all of them, 84+) This was supposedly so that you can't lock your keys in the car but I think it's annoying. My understanding is that there are two switches in the lock actuator (locked and unlocked) or at least this is what I was told. My 89 does not have any mechanical connection from the lock-cylinder (key) to lock the car. The "lock" ear that appears on earlier cars is simply not present. only the "unlocking" ear remains so that the car can be unlocked even if the battery is dead. Locking the car from the outside is (at least on my car) only done via the central locking (that is, if your battery is dead - using the key to lock the car does nothing) and there should be a switch up at the lock-cylinder to faciliate this. So three power-lock related switches total; two to indicate locked or unlocked and one momentary switch to lock the car from outside via the key.

I'm afraid my car was more or less gutted by alarm installers. The central locking button no longer does anything and my flashing lock-knobs don't work. I have a 12 pin connector with some cut wires and nothing attached to it near the passenger side hood strut; I believe this is where the central locking control-box is supposed to be located. What I don't understand is that locking and unlocking one door from inside the car does lock or unlock the other door still. So either I'm wrong about my missing central locking box, this particular behavior is not controled by the box, or they have wired the alarm such that it still performs this action in place of central locking. This is the only aspect of central locking that still works on my car - It cannot be locked via a key from outside either. I have to either lock it with the keyfob remote or with the passenger side door.

And that's everything I know about the system to date, it is not a priority for me at this point but I'd love to see a comprehensive thread on it.

I had a similar issue with mine. It turned out to be the electronic sensor ring on the drivers door...