when driving my E320 4matic wagon, if I push any where on the inside of the driver's door, the front dome lights turn on for a couple seconds. Sometimes even the doors will unlock then lock again, along with the dome lights coming on as well. This will also happen if I make a sharp right turn. The door is not loose and the plunger switch for the door seems to be wokring properly. Any suggestions would be helpful, because this is very annoying. Just leaning my elbow or knee against the door will make the dome lights flash.

 

Hi,
Try extending the plunger on the door switch by 2 mm or so or alternatively place an abutment (sticky pad or similar) on the surface that the door switch plunger contacts.
This should fix the dome light part of the problem.
However the unlock/lock of the doors is strange unless there is some type of linkage between the locks and the door open signal. I didn't think there was.
Of course if auto locking is switched on the doors will auto lock at 5mph.
Hope this helps.
Stuart

 

Thanks, but the door plunger is not what is triggering the dome light to turn on. I tested the plunget and it needs to come out about an inch before it triggers the dome light to turn on. When I put pressure on the inside of the door, the door is not even moving a fraction of an inch, but the light still comes on.

 

i'm a little uncertain how you measure the 1" travel and would defer to you on that fine and important point. but the symptoms you describe are so typical...to the letter....of failing door pin/switch. did you do as snanceki suggested? build up the end of the pin/switch using duct tape or something.....or tape the small spot on the door itself opposite the pin head.

the door locks cycle because the car is designed to lock them when >9mph. the cost for replacement of the switch is less than $20.

 

OK. You seem to be CERTAIN that it is not the door switch but this is a good place to start.

Next. So EXACTLY where do you push on the door for it to come on. Surely it can't be ANYWHERE as you suggest. Also what does "push" mean. With your finger, arm, shoulder? More definition MAY help.

Any other warning lights / strange behaviour however disconnected you may think such symptoms are?

Can you please describe your vehicle and the problem in more detail. For instance Age, mileage, when problem started, link if any to servicing/repair etc.
Also what position is your dome light switch in? Presumably on door. Correct? If so try turning the switch to OFF. This will of course kill your interior light, and the dark nights are coming, but it will confirm that it is the door switch earth feed that is causing the problem.

Subject to the above I suspect you are going to find that your PSE (Pneumatic Security Equipment) has gone bad. This is the module that controls the dome light, the security system, the door locks and exterior bulb monitoring. I didn't go for this immediately since modules are relatively expensive 300USDAPPROX fitted according to the last case similar to this. However your symptoms (as I currently have them) DIFFER SLIGHTLY from the classic symptoms.

To confirm that it is the PSE (in the boot or under the rear seat somewhere with yellow tubes coming out of the top) you could remove the electrical multipin block connection to the PSE (the one with a small WHITE and a small GREEN wire going to it). Not sure if it is the white or black multiplug without reference to the manuals.

Let us know any further info and i will try to save you the money for a new PSE.

Alternatively you could take the car to a MB dealer and they will use diagnostics (like using a scanner to determine engine DTC Diagnostic Fault Codes) which should identify a fault STORED on the Body CAN (computer). On the other hand they will charge for this and there MAY NOT be a code stored.

Stuart

 

Thank you all for making me see the light. It is in fact the plunger button that is the culprit. I put some tape on the door to build up the contact area where the plunger hits the door ...and the problem is solved. Now when I get time I will replace the switch. Thanks for saving me money that my dealer would have gladly taken from me.