inside the driver's door... - PeachParts Mercedes-Benz Forum

thebern · #1 05-20-2002, 03:08 PM

Still having vacumm problems will post specifics later.

Inside the drivers' door, connected to the locking mechanism is a black plastic (servo?) plunger like thing that is about 6 inches long and mounts to the aft of the door. It has 2 electrical wires going to it.

What is it? What does it do?

mikemover · #2 05-20-2002, 06:30 PM

Are you sure it's electrical wires attached and not vacuum lines? Sounds like you're talking about the "sending unit" (I don't know the correct MB term for it) that sends vacuum to the other doors telling them to lock/unlock when you turn the key in the driver's door.

I've got an elusive vacuum leak in my locks...All of the vacuum actuators check out fine, and all the vacuum lines that I can see without pulling everything completely apart seem to be good...I'm stumped! Anyone have any suggestions where to look next?

Mike

the_good_fellow · #3 05-21-2002, 12:46 AM

On the driver side it does have wires(83 300SD) which activate the pump in the trunk to lock/unlock other doors.

Mike, did you check the one for fuel filler door?

mikemover · #4 05-21-2002, 01:16 AM

Ah, that's right...I forgot the later models had the electric pump in the trunk.

So that sends a signal to the pump, instead of just sending vacuum in the right direction. Cool.

Yeah, I checked the fuel door, the trunk lock...all of them check out. Maybe my vacuum reservoir is leaking? Tired vacuum pump? Sometimes the tranny doesn't seem to shift as solid as it should, but other times it's fine. I dunno....

Mike

jcd · #5 05-21-2002, 07:16 AM

Mike,

I had a couple of leaks due to a crack in the vacuum hose where it runs from the door post to the door. The way I found it was turning off the car and opening each door, one at a time, and seeing if that resulted in a vacuum loss. I confirmed it by hitting the MityVac and listening for a hiss around where the rubber hose/gasket runs from the door post to the door.

Very..........Very tricky to find and fix.

Hope this helps,

JCD

mikemover · #6 05-21-2002, 07:43 PM

JCD,

Thanks, man...I'll have to give that a try!

Mike

speedy300Dturbo · #7 05-21-2002, 08:43 PM

Your car does not have any electronics inside the door, unless you have power windows. Sounds to me like this is an aftermarket electric door lock motor, used to push the driver's lock upward electrically, for a keyless entry system that the previous owner may have had.

mikemover · #8 05-21-2002, 09:05 PM

Hi Speedy300Dturbo,

Was that to me, or the original poster's question?

I know my locks don't have any electronics, but apparently the later models with the electric vacuum pump in the trunk do. I'm not as familiar with those.

Mike

speedy300Dturbo · #9 05-22-2002, 12:27 AM

That was to the original poster. The W126 models had electronics in the drivers door for the locks... but in his case they are definetely an aftermarket power door lock system. How do I know? Because I installed keyless entry on my car and needed to install an electric door lock servo like what he described.

mikemover · #10 05-22-2002, 12:32 AM

Aha! The mystery is solved.

Wonder how much trouble it would be to install keyless entry on my vacuum lock system? Guess I need to get the darn thing to stop losing vacuum first, eh?

Mike

speedy300Dturbo · #11 05-22-2002, 06:26 PM

Keyless entry is harder to install on the 116 and 123 models, because you will need to buy a door lock motor which will push the driver's door lock plunger upward. With enough perseverance, you'll find the correct spot for it to engage smoothly. Do not rush this. The easiest way to test the movement of the door lock plunger and your new door lock motor, is with the door open. To make the lock "think" that the door is closed, press on the "claw" part of the door latch mechanism until it latches. Press again, so now it thinks that the door is fully closed, even though it is open. Make sure everything engages smoothly.

The rest is a breeze. Run the wires to the keyless entry unit, hook it up to +12volts, ground it, and run some wires to the parking lights. Have fun!

thebern · #12 05-26-2002, 05:43 PM

It is indeed an aftermarket unlocking thing-a-majig that was wired to the alarm system! thanks