'88 300E CENTRAL LOCKING
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Joined: May 2019
Posts: 24
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From: Washington, D.C
1988 300E, 1993 400SEL, 2000 BMW M Roadster; 2001 Toyota 4Runner
'88 300E CENTRAL LOCKING
The central locking on my W124 300E (1988) stopped working suddenly yesterday. Unlocking driver's door does not unlock other doors (or trunk). Everything needs to be unlocked and locked manually, including the trunk. If I manually lock the passenger side doors with the driver's door still unlocked, and then open the driver's door, it sets off the alarm, which I can then shut off by turning the key in the driver's door lock counter-clockwise to unlock (even though it is already unlocked). Locking it does not turn off the alarm. It has always worked fine since I've owned it (about two years) though the pneumatic lock has always seemed sluggish to me, though I have nothing to compare it to other than modern cars, all of which lock almost instantaneously. It is not a fuse problem. I haven't found anything on the threads that addresses this directly. I am not particularly knowledgeable about mechanics or electrics, but do love these cars. Does anyone have any suggestions?
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From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
The central locking on my W124 300E (1988) stopped working suddenly yesterday. Unlocking driver's door does not unlock other doors (or trunk). Everything needs to be unlocked and locked manually, including the trunk. If I manually lock the passenger side doors with the driver's door still unlocked, and then open the driver's door, it sets off the alarm, which I can then shut off by turning the key in the driver's door lock counter-clockwise to unlock (even though it is already unlocked). Locking it does not turn off the alarm. It has always worked fine since I've owned it (about two years) though the pneumatic lock has always seemed sluggish to me, though I have nothing to compare it to other than modern cars, all of which lock almost instantaneously. It is not a fuse problem. I haven't found anything on the threads that addresses this directly. I am not particularly knowledgeable about mechanics or electrics, but do love these cars. Does anyone have any suggestions?
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Joined: Nov 2015
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From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
Does your w124 have the Anti theft alarm ATA module? I believe that also controls the central locking system.
You can dig further by looking into the wiring diagrams ====>
https://freescruz.com/.priv/W124/Ind...rbleShting.htm
You can dig further by looking into the wiring diagrams ====>
https://freescruz.com/.priv/W124/Ind...rbleShting.htm
Thread Starter
Junior Member
Joined: May 2019
Posts: 24
Likes: 2
From: Washington, D.C
1988 300E, 1993 400SEL, 2000 BMW M Roadster; 2001 Toyota 4Runner
Does your w124 have the Anti theft alarm ATA module? I believe that also controls the central locking system.
You can dig further by looking into the wiring diagrams ====>
https://freescruz.com/.priv/W124/Ind...rbleShting.htm
You can dig further by looking into the wiring diagrams ====>
https://freescruz.com/.priv/W124/Ind...rbleShting.htm
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From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
Thanks, Khomer2. I haven't the slightest idea whether my W124 has the anti-theft module you refer to, and unfortunately the wiring diagrams might as well be in Chinese to me. Is it possible it's the anti-theft system that is the problem? Though I would note that anti-theft seems to work. Today I got out of the car, locked the driver's side door and then realized the RR door was unlocked. When I went around and opened it in order to push the button down manually, the alarm went off.
Vacuum check-
You can start checking the central locking vacuum connections too. You may have a leak somewhere.
Thread Starter
Junior Member
Joined: May 2019
Posts: 24
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From: Washington, D.C
1988 300E, 1993 400SEL, 2000 BMW M Roadster; 2001 Toyota 4Runner
You have the ATA if the alarm when off - btw, the Alarm module is located on/under the floor board, passenger side. Pull the heavy carpet up and backwards. There is a screw securing the cover plate you will see.
Vacuum check-
You can start checking the central locking vacuum connections too. You may have a leak somewhere.
Vacuum check-
You can start checking the central locking vacuum connections too. You may have a leak somewhere.
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MBWorld Fanatic!
Joined: Nov 2015
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From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
When I turn the DS door key CW, I watch for the timing of the door plungers to see how long they take to lock (go down) relative to the DS plunger.
If it's not instant (within 1-2 secs), then there's a good possibility there is a (small) leak somewhere.
Ah.... we all get leaky as we age into the Sr, years....
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Thread Starter
Junior Member
Joined: May 2019
Posts: 24
Likes: 2
From: Washington, D.C
1988 300E, 1993 400SEL, 2000 BMW M Roadster; 2001 Toyota 4Runner
My simple vacuum test on these older great MBs is:
When I turn the DS door key CW, I watch for the timing of the door plungers to see how long they take to lock (go down) relative to the DS plunger.
If it's not instant (within 1-2 secs), then there's a good possibility there is a (small) leak somewhere.
Ah.... we all get leaky as we age into the Sr, years....
When I turn the DS door key CW, I watch for the timing of the door plungers to see how long they take to lock (go down) relative to the DS plunger.
If it's not instant (within 1-2 secs), then there's a good possibility there is a (small) leak somewhere.
Ah.... we all get leaky as we age into the Sr, years....
)
MBWorld Fanatic!
Joined: Nov 2015
Posts: 1,456
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From: Westcoast/Interior
02w163ML500 / 97w210E50AMG / 99w202C230k / 95w124500e-wip
Another note/ checklist I have on the w124s:
Can you hear the vacuum pump whirring?
When you activate the door locks for both lock and unlock, if you hear it whirring, then typically, there is nothing wrong with the door switches for the power lock system.
But, If the pump whirrs for say, 5 seconds or longer, then you have a leak, either in one (or more) of the lines, the door actuators, or inside the pump itself.
Can you hear the vacuum pump whirring?
When you activate the door locks for both lock and unlock, if you hear it whirring, then typically, there is nothing wrong with the door switches for the power lock system.
But, If the pump whirrs for say, 5 seconds or longer, then you have a leak, either in one (or more) of the lines, the door actuators, or inside the pump itself.
