w124 doors all relock after a few seconds
 

Hi All,

My 1989 230E relocks all the doors after a few seconds of unlocking. The car is not fitted with an alarm system. Sitting inside the car, I can hear a long drawn out buzz somewhere in the rear after the relock. Sometimes while driving with all the doors unlocked, the doors all lock when I turn off the engine and remove the key from the ignition. Where should I look? There is serious risk of a lock out - like somebody opens the doors, places the key on the drivers seat, closes the door and before the know it...

Thanks for any help.
Marco

I'm no guru, but I would try disconnecting the power for as long as 10 minutes, then reconnecting. First I'd pull the fuse. If that doens't work, disconnect the battery for as long.

Sounds like the vacuum pump is on its way out too.

By disconnecting the power for 10 minutes, what am I supposed to see?

I'm guessing he meant to reset the system...

I had the same problem. It was the trunk lock causing it.
When you unlock the car the the rubber part of the trunk lock vacuume activator keeps the trunk lock open. In my car that part had cracked and it was letting the locking mechanism of the trunk to go back to locked position. There is the sensor at the trunk lock that tells the central locking system that the vacuume locking mechanism of the trunk is going back to locked position. The central locking system thinks you put a key into the trunk and locked the car from the trunk lock. This was causing auto locking in about 1-5 minutes. I really don't know the exact name of the rubber part. That part is located on top end of the vacuume activator.
You should open the trunk and open one of two plastic covers at the back of the trunk lock. You should pull the cover at the right side and see if the rubber of the vacuume activator is cracked and watch if activator is going back to locked position after you unlock the car. I need that rubber part too. If you find it cheap let me know where you found it.
Good luck.

Hurshi

I've seen the trunk mechanism do it too.