gaineserau

I have been on these boards a lot performing all sorts of DIY's off of a wealth of info--a big thanks to everyone . I wouldn't post, but I have found NO one that has had this same problem with the door locks...

Rear left door of W164 ML320 Bluetec will electrically lock but WILL NOT UNLOCK. even the lock part was intermittent.

1. I have already replaced the entire lock assembly myself (had completely dead one on front pax door--that problem was solved...) the door now locks perfect but WILL NOT UNLOCK!

2. My imitation STAR scanner (which will read the individual components of the car) shows that when I enter the front SAM (I believe this is what controls the locks) if I click on (Left rear central locking) I can see both the UNLOCK and LOCK commands are being sent by the SAM.

3. When looking at the white flat plug into the lock actuator, it appears that the purple wire and off-white wire at one end are what send the lock (and maybe in reverse charge direction, unlock) commands. Hooking a 12V tester up I can see it light up when grounded with a LOCK command. But I cannot find one wire in that plug that lights up with an unlock command.....

4. I've disconnected and electrically cleaned the door wiring plug in the door jam.


Alright folks, what am I missing? Is this a broken wire somewhere? and if so, does anyone know what wires send the unlock command to the left rear door?

GO!!!!........

(Many thanks in advance)

Euler

You may have a door module, N69/2 problem. The attached shows two wires from the door module going to the door lock motor M(ZV) in unit M14/5. The other motor in M14/5, M(KG) is I believe another lock motor driven by the keyless go system, unit N69/5. It appears that the normal operating mode is to reverse voltage polarity to the lock motor to unlock, so the same two wires operate for both directions. Based on what you have described I would guess a problem with the door module and not the SAM.


For some reason my image will not upload.

gaineserau

Wow I am VERY grateful for this info!

A few questions. Do you know the door control module location? The part number for this N69/2 controller? I do indeed have keyless go on my car so I'm not sure if that changes anything. I thought that the current was reversed! Just didn't know there was another module between the actuator and the SAM.

Euler

Euler

I believe the module is actually in the door as it helps limit the number of wires passing through the hinge. Anyway, see above. I got the images to attach. They are for the right door. The difference is that the left door diagrams have many more sheets for things like master window and mirror controls.

gaineserau

Great info again thanks!

However, I don't remember seeing an actual door control module inside the left rear door....Is the entire left rear door controlled off of the front left door control module? It looks in the last picture like there is a control box in the left rear door.

Euler

I've never been in the doors, but I am going to assume that there is a door module in each door.

Melvin Phillips

Mike Tildesley

Hello did you find an answer to this I'm on my third door control unit they've all worked for a couple of hours then just shut down drivers door will not lock or unlock with fob

Maj. Dundee

And what happens if you use the mechanical key?

Mike Tildesley

if I reach in and lock door from rear yes the key will unlock it

Maj. Dundee

That doesn't answer my question. Do you know you have a mechanical key in the fob?