Hi everybody. For those who remember me (especially Augapfel), my car's central locking totally stopped working last year and then meraculously "healed itself" a few weeks later and has been great ever since (until last Friday).
Problem - all the doors plus trunk will lock/unlock 100% from the drivers door, but from the trunk lock only the trunk will lock/unlock. Am I correct in my assumption that it is an electrical problem only? - as in perhaps a switch in the trunk which is either not making contact or is broken? Forgive me if this is a stupid assumption as I am an electrical moron.
Any advice will be appreciated. Please include advice on how to access the faulty component. Thanks guys.
The central locking systems on our cars are vacuum operated. I would start by checking all the vacuum lines to the six lock assemblies (4 doors, trunk, gas door). The vacuum unit itself is located under the right rear passenger seat. Based on your discription of the problem, the trunk assembly would appear to be the problem.
Thanks Jayare, but I am sure that there is nothing wrong with the vacuum system as I can lock/unlock everthing from the drivers door. Its when i try from the trunk lock that only the trunk locks/unlocks - this is why I feel that it must be a breakdown in the electrical connection from the trunk (the vacuum pump is simply not activated)
Suggestions please? Thanks
I am in Minneapolis on business for the next few days so I can't go out and check anything at the moment, except the weather. I still think you problem is with the trunk lock. Take all the conntections off and check that they are clean and well attached.
Thanks - I will do so over the weekend if I get a chance. Once the problem is sorted out, I will post the reason for the problem here to help any other person who experiences the same problem
Thanks - I will do so over the weekend if I get a chance. Once the problem is sorted out, I will post the reason for the problem here to help any other person who experiences the same problem
I don't know which model/year you have but I had the same issue with my 93 500E. A
tech told me to disconnect the battery for a minute and reconnect to reset the system.
It worked perfectly after doing so.
Each of the 3 lock cylinders (front doors and trunk) is connected to a rod that goes to a vacuum actuator/switch assembly. When you unlock any 1 location with the key the linkage unlocks that door but also moves the vacuum actuator diaphragm to close a switch. The signal from the switch then "goes" to the vacuum pump (with circuit board) that is located under the rear seat cushion, RH side. The pump then runs in the appropriate direction for opening or closing all the *other* portals via the vacuum actuators.
In the situation that you describe I'd expect to find a defectove or disconnected vacuum servo at the trunk. If you stand behind the middle of the car, open the lid, lean forward until your head is touching the trunk floor, and look toward your knees, at the right of center you will see a rectangular flap. It is through this flap that you can access the vacuum servo and it's connector.
First check to see if the connector is okay. Removing and installing it may solve the problem.
Thanks to both Augapfel and Arno for the advice. I will address the problem over the weekend as it is not an extremely urgent issue - its just a pain in the a** having to walk around to the front door every time to lock/unlock the car, instead of doing it via the trunk lock.
Last edited by Benzisgreat : 12-05-2007 at 11:46 PM.
Wow - I am a lazy you-know-what. Its a month since the advice given by Arno, Augapfel and Jayare about getting the central locking to work from the trunk lock and only yesterday did I do something about it. Guess what? - Arno's mechanic was right! I simply disconnected the battery for a while (and used the opportunity to clean the terminals and other build-up on the mounting plate etc). Re-connected the battery after about half an hour and IT WORKS PERFECTLY. Wierd but who cares!
Thanks once again
I don't remember what year car you have but something must be vastly different than the 86-88 124s that I'm familiar with. Either that or some non-North America cars are vastly different.
On NA cars all the vacuum servos are connected via a common pipe system. There's no way that disconnecting adn reconnecting the battery would fix the problem that you describe. Anyway, glad it's fixed.
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