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Door doesn't unlock with the key.

7K views 9 replies 4 participants last post by  300Dman 
#1 ·
Hey guys. I've got a 240D and I've been facing with this issue from the time i got this car. The front door on the passenger side doesn't unlock with the key. The car is not centrally locked (As the vacuum lines which lock all the doors have been bi passed and made all the door lock and unlock individually). The door can be opened by pulling the knob from the inside but when I push the lock button and close the door and then try to reopen the door using a key, it doesn't unlock. The key doesn't turn at all. Neither on the left nor the ride side. It just stays stuck. Found a way about how to open the door handle from mercedessource. However, what exactly may be the issue? Will opening the handle alone will be enough to work upon and fix the issue? Appreciate your help guys.
 
#2 ·
It is possible the rod that connects the tumbler to the locking mechanism is no longer connected to the locking mechanism inside the door. Or, the mechanism is stuck.

Opening the door and looking to inspect would be my recommendation.

It's happened to me before, except the door turned freely with no resistance. The rod I spoke about earlier was not connected to the mechanism. I had to loosen the handle (2 screws on door jamb inside black rubber cover, and 1 screw on front tip of handle accessed through inside panel of the door) and reposition to get the rod back in place.
 
#3 ·
Thank you MBeige for the quick response. Will try the resolution you've given. And I'd like to mention another point here. I live in India and the w123 pictures you've uploaded on flickr actually inspired me to own one. And so I got this w123 240D US spec (Very few/Countable models in India) last year same time. I've to say you've got the best w123 out there I've seen. Thanks again for the solution.
 
#5 ·
the mechanism in the passenger door has not just locked and unlocked states, but also another sliding part which can be in one of two positions, indicating whether the vacuum actuator or the lock cylinder has primacy. if this mechanism sticks in the vacuum-linked position, a key turn will not be able to take control of the lock. remove the door panel and inspect the positions and transitions. you can manually change the mode by pulling the S-sprung linkage apart (up & down) or pushing it together. hope this helps.
 
#7 ·
I did not entirely understand your description so I will just say what is happening with mine.

There is supposed to be a Master Key. The Master Key opens everything.

There is a Valet Key. That Key only opens the Drivers Door and works in the Ignition Lock. It will not open the Glove Compartment.
That key will also not turn the Trunk Lock Tumbler.
However, only if the Trunk lock Tumbler was left in a specific position when you turn the Key on the Drivers Door Vacuum will actuate and unlock the Trunk.

If someone replaced the Ignition Tumbler with a generic type Ignition Tumbler the Key will not work on any of the other locks.
 
#8 ·
Master key also opens front passenger door but doing so does not unlock the whole central locking system.

Valet key is only for driver door and ignition lock as mentioned.

OP cannot open passenger front door with key. It is possible, like you said, that the tumbler was replaced at some point.
 
#9 ·
Okay. So This is I think the issue is. Cause the trunk lock doesn't open as well using this key. In fact the key never fits in to the trunk lock. The key works only on the driver side door and the ignition. However, I'vent yet opened the door panel yet. But this seems to be something close to the answer I was looking for. Will check the lock when I open the door panel sometime in future. Thank you both Mbeige and 300Dman :)

I've another question here, the handle which we pull in order to open the door has spring action in it. So when we pull the handle it flexes out a bit and then should go back. The rear door handle however doesn't go back after I leave it. It stays in the same position (Stretching out). What may be the reason for this? Is there any spring present inside it which might be broken? Appreciate your response :)
 
#10 ·
In order to pull off the Door Panel on the inside where you Pull the Handle to open the Door there is a thin Plastic insert that covers a single Screw. That screw needs to be removed to get the Door Panel off.
The Plastic Map Pocket is attached to the Door at the Front. To loosen it needs to be sort of pushed forward and up and the same time.

For the Trunk Mbeige posted a Pic of a Vacuum Diagram. If you locate the Vacuum Line going to the Trunk Lock and apply Vacuum to that you might be able to open the Trunk.

If the Trunk Lock Button will not push in at all that is a whole other problem.

Over here if you give the Mercedes Dealer your VIN Number they can cut you a New Master Key and even get a New Key and Ignition Lock Tumbler set for your Car.
However, they want to see the Car itself and the Registration so you can prove ownership of the Car.
I am guessing they can also do the same from India even if it means the Key would have to come from Germany.

If it looks like your Car has some sort of Alarm System on it look at the bottom left side of the Rear Seat and see if there is a Cable with a loop on it. If so that is a Pull Cable to open the trunk in the event of a Alarm System issue.
 
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