Mk2 Central locking connector pin configuration - drivers door

[Duncsuk]

Unfortunately, the central locking is playing up.  Everything works perfectly except the driver's door 'unlock' when using the remote.  The door can be unlocked using the key and can be unlocked (assuming the deadlock is not on) from the inside.   I have checked fuses, checked for broken wires (nothing obvious) as well as removing the door panel.   As I mentioned, everything else works fine.

It seems it is not possible to pull out the connector (of the door wiring loom) hidden within the door frame without removing the door, so before I do that, I wanted to check that, when applying the appropriate signal (+12V ?, earth ?) to the relevant unlock wire of the loom, the door lock actuator was indeed ok (suggesting a broken wire/ poor contact somewhere else).  

But, the loom that runs from the door connector (hidden in the pillar) to the lock actuator plug in the door itself, which has nine wires (6 lighter gauge, 3 heavier),  are ALL COLOURED BLACK !!!!!   What's all that about ???

Anyway, I can access the 10 way plug in the door so can track back the nine wires and identify them, if I knew the pin configuration of this actuator module plug/connector itself ?

Can anyone help ?

TIA ....

[Micro]

Does the connector look like the one in the picture? (It appears to be the drivers door connector from the wiring diagram)

Pin 7, 8 and 12 appear to be connected to the various motors/switching. It all appears to be on page 105 of the wiring schematic (This is all assuming you have no drivers/other door modules). I think the other connections are just sense connections (for door ajar switch, other door items).

 

[Duncsuk]

Thanks for the reply.  Unfortunately, I think the connector you mention is the one buried in the door pillar .. but you give me the idea to try and trace along from that one ?  Will check out  page 105 too.

The one I'm referring to is shown below (and as you can see all wires are BK !!) although only 9 wires are used.

[Dan62]

The same two wires are used for locking and unlocking, so if the door locks using the remote but does not unlock its not the wiring.

The drivers door has its own unlock relay and there is another to unlock the passenger doors, they all use the same lock relay.

From your post description of it just being the drivers door unlock being the problem it looks like the relay is the issue.

Unfortunately the relays are internal components of the GEM.

 

[Duncsuk]

Thanks for the update.  I did start to suspect that relay.  Real pain it's part of the GEM.

I guess to prove the theory, if, when the doors are locked, I disconnect the wire between the GEM (relay) to the door and temporarily connect it to 12V (which is what is the relay provides during unlocking) and then try to 'unlock' with the remote, it should open.   Does that make sense ?

I'm assuming that when unlocking the car by key, the GEM relay (for the driver's door) is not used as such ?

TIA 

 

 

[Dan62]

If you disconnect the wire from the GEM and apply 12v to it the door will / should unlock straight away. (Connector C100 pin 25 White/Black wire)

If this works and you don't want to replace the GEM I don't see why you can't connect the above wire to the passenger unlock circuit. The only thing that won't work is the drivers door only unlock feature.

Using the key in the lock mechanically unlocks the door, not requiring the motor to operate to unlock it.

[Duncsuk]

Thanks Dan ..  spot on mate .    Worked a treat
 

[Dan62]

Well done, thanks for the update.

[dimebucker]

Sorry to revive this old thread... but how do you access C100?

(I have drivers door functioning correctly but all others stuck on locked)

[Duncsuk]

From memory, you access all the connectors in the passenger footwell.  There are two twist locks to undo the gem module and the complete panel drops down (on hinges).  I can't remember if you need to unclip from the hinges to improve access.  C100 is a big connector - 46 way I think.  Again, from memory, I left it in place, cut the problem wire and spliced it with a feed that was working correctly.  And touch wood, has been fine ever since.  I do have a large .pdf with wiring diagrams and more importantly wire colours I can send you if you PM me 🙂

[dimebucker]

So I located the wire (Pin 18 for all other doors... C100 seems to be the big brown connector) and if i cut the wire, which end do i send 12v down... the end going into the junction box in footwell... or the end going into the car somewhere?

Sorry, im confused about which direction things are located!

[Duncsuk]

Assuming the root cause of your problem is the same as mine was, you'll need to put 12v into the wire that goes into the car (lockls) and leave the cut wire, taped off, coming out of the connector.   You can first test it by cutting the problem wire, feeding it with 12v from the battery for now and the doors should unlock.  If that doesn't resolve the problem, you'll need to investigate further.However, if you're in any doubt, maybe seek further guidance on here or call an auto-tech 🙂 

If that doesn't resolve the problem, you'll need to investigate further.

Hopefully, I've attached a photo which shows the cut wire (with black tape) and new red connector joining the other part of the cut wire to the functioning unlock signal.

 

Hopefully, all makes sense.

[dimebucker]

It worked!
Thanks so much for the help, saved an expensive trip to the garage! 
Now I only lock the door manually and everything is fine.

For the future i'm thinking of putting a small momentary switch somewhere on the dash that would apply 12v to that cable to unlock frozen doors.... then I can use the remote locking again.

[Duncsuk]

👍