Exploring the Inside of the Late-124 Driver's Door - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 08-03-2013, 02:46 PM

While doing some work on the inside of the driver's door of my '95 E300 I took pictures to share with the group. The intent here is not to show you how to do anything but just to label the various pieces so that when you remove the door skin for the first time (there's always a first time!) you'll know a little about what you're seeing.

Earlier 124s do not have some of the bits and pieces shown in these pictures. Speakers, the white plastic rain cover on the pneumatic lock actuator, the black plastic cover over the door check, and the electrically adjustable outside mirror were all added at various times during the model run. If you can date these changes, chime in. If you can add pictures of something I've left out, please do so.

The front passenger door is a mirror image of the driver's door; the rear doors are similar but I've never seen the insides except on my '87 300D.

Jeremy

1. A sensor for the alarm system lives in the end of the door. It's easy to pry out, gently, with a knife blade. The yellowish plug can be disconnected; its wire goes to the outside lock cylinder and must be removed with it. I have more pictures of this procedure if anyone needs to see them.

2. Here's the lock cylinder with its alarm wire and the yellowish plug. FSM says the key is necessary to remove the lock but I've also heard that it's possible to remove without a key (example: in a wrecking yard). I don't know how, I've just heard it's possible.

3. This is the door handle and its mounting bracket removed from the door.

4. The door latch is mounted with three screws (very tight!). Late models use Torx but early models may use Philips.

5. The pneumatic-electric actuator for the Central Locking System mounts with two screws. It has an electrical cable and a plastic pneumatic (vacuum-pressure) hose plus a mechanical link to the latch and from the door button.

6. Here's the electrical plug for the pneumatic actuator. (It's hard to see.) Some other bits and pieces are identified in this picture.

7. This is the plastic shield that Mercedes added to protect the pneumatic actuator from water and maybe from people trying to break in. It's held by friction and one screw and I had a miserable time getting it back in.

8. The electric window regulator is attached with 5 nuts. Make sure they stay tight!

8. Here's what the regulator looks like with the window all the way down. Make sure the grease isn't dried out on the big gear and the sliders.

9. This is the terminal block for the electric window's motor. The motor is not electrically grounded. One polarity makes the window go down; reversing the polarity makes it go back up. All that is done with the window switches. If you measure the voltage across the two terminals you'll get either +12V or -12V depending on whether the window is going up or down and zero volts if it isn't moving.

10. This is the door check (holds the door open) as removed from the door. It's attached with three screws, one of which can be accessed only by first removing the door skin. Any time you have the door skin off, give thought to removing, checking, and re-greasing the door check. It will last forever if you take care of it. I don't remember my '87 300D having that black plastic cover so maybe it was added at a later date.

11. Here is a picture of the seat switch assembly and the inside door release. The seat switch buttons and the black plastic escutcheon under the door release must be removed before the door skin will come off. I put the pieces back on for the photo.

12. Finally, here's the wiring and electrical connector for the outside mirror. Unplug the connector and remove the three screws to remove the mirror assembly. Early models have a simpler plug (heater only) and a handle to adjust the mirror. Passenger mirrors are all electrically adjustable but I think have two plugs (memory fails me).

END

benedict · #2 08-04-2013, 04:01 AM

Jeremy,

You've got some nice features there that were never an option for me.

As you know I have the exact same car, well at least I thought I did. Security was never an option, electric seats were never an option and I'm guessing Bach sounds better in your car as we were never offered door mounted speakers.

I've come back to edit my post. In my moment of envy, I forgot to say, another good informative post.

Jeremy5848 · #3 08-05-2013, 02:16 AM

Thanks for the comparison. I didn't realize that those items were never offered in Oz. Was this lack just on the '95 E300 or on all 124 Mercedes cars?

Jeremy

benedict · #4 08-05-2013, 07:19 AM

Quote:

Originally Posted by Jeremy5848

Thanks for the comparison. I didn't realize that those items were never offered in Oz. Was this lack just on the '95 E300 or on all 124 Mercedes cars?

Jeremy

Electric seats were offered on some pre-update petrol versions but were never offered on the E300D. Leather was never optioned for the E300D either. Not sure of MB Australia's thinking with this but maybe because the purchaser of diesel had economy on their mind and maybe wouldn't necessarily want the bells and whistles.

We have a watered down HVAC system also. Just two manual knobs in place where you have a row of press buttons.

Speakers in the door- I've never seen a W124 with that option here.

Alarm system was available on the post-update petrol versions only, mainly the E220 which was a 2.2 litre petrol (Gassers I think you call them in the US)

One good thing we didn't get (although not good from the environments point of view) was pollution control. Catalytic converter yes but no return of the carbon back into the engine via the EGR valve, so things are a bit cleaner inside.
Ben

Zulfiqar · #5 08-05-2013, 09:13 AM

Those screws are strange, my car has csk type philips screws holding the latch on the door.

My car has a working alarm (btw thanks for the wiring tips for conv module - got the auto feature working) - have the sensor on the door etc. The only difference is that my car has no memory seat.

pwogaman · #6 08-05-2013, 09:26 AM

Nicely done!

Jeremy5848 · #7 08-05-2013, 11:49 AM

Quote:

Originally Posted by pwogaman

Nicely done!

Thank you!

Z, my '87 300D Turbo also had Phillips screws holding the door latch. I had assumed the switch to Torx was made sometime in the early 90s but maybe it was actually part way through the '95 model year. My car was made in January 1995 -- how about yours? If it was made earlier we can guess that the change-over was made sometime in between.

I suspect the production line operates on a philosophy of "use up the old parts before switching to the new part." Your car may have been made on a line that happened to have a big stash of Phillips screws.

My 1996 E300D (W210) also has Torx screws holding its door latches.

Ben, I've never understood the logic of why Mercedes chose to offer some options on one car and not on the next one. Note to Zulfigar: the memory seat on the driver's side was part of option package E2, according to the factory sales brochure "1995 / E-Class / Mercedes-Benz." E2 also included a telescoping steering column and the "high-performance sound system with ten speakers."

In America, the fancier and more expensive versions of most car models have almost always included bigger, more powerful engines. (I am deliberately leaving out of this comparison big pick-up trucks with enormous turbo-diesel engines). Mercedes seems to have considered the diesel model therefore to be the "entry-level" car of its class. Since people buying entry-level cars are usually price-driven, they get fewer expensive options.

Smog stuff and other things mandated by law aside, I have no idea why Mercedes would market their cars to Australia with so few options. Maybe the Germans still think everyone in your beautiful land was recently transported. (BTW, many of us here in the States would happily trade you for your manual climate-control system: the automatic version can be a real PITA when it breaks.)

Bonus feature: the little dash speaker on the driver's side (part of the sound system, left or right side as the country requires) has two voice coils. This speaker was used with the optional cellular telephone, hence the second voice coil. A nifty mod by M-B, most folks don't even know it exists. The second voice coil can be connected to any monophonic sound source -- a scanner, ham radio, or hands-free cellular system.

Jeremy

Zulfiqar · #8 08-05-2013, 01:14 PM

hmm - makes sense, my car has a production date of 10/94, and is the oatmeal with no syrup model.

no memory seats
no telescope wheel

It does have the active bass audio with woofers in the front doors. btw thanks for the enlightenment of the other voice coil in the driver side front speaker.

Jeremy5848 · #9 08-05-2013, 01:39 PM

Quote:

Originally Posted by Zulfiqar

hmm - makes sense, my car has a production date of 10/94, and is the oatmeal with no syrup model.

no memory seats
no telescope wheel

It does have the active bass audio with woofers in the front doors. btw thanks for the enlightenment of the other voice coil in the driver side front speaker.

Yeah, Mercedes referred to the two audio systems as the "Active Bass sound system with 6 speakers" and (part of option package E2) "High Performance sound system with 10 speakers." It looks like they installed the option packages randomly on some diesels and not on others.

Also unfortunate that none of the E2 options are DIY retrofittable, at least not without a hell of a lot of work. OTOH, you have fewer things to break (but by that logic we should all be driving the 240D with stick shift and no sunroof, etc.).

If you do happen to connect something to the second voice coil in the driver's speaker, note that the sound system and the second source will be heard together; this doesn't hurt anything but it can be confusing -- your police calls will be heard simultaneously with Janis Joplin singing "Mercedes Benz." The cellular phone installation had a special connection that automatically turned off the sound system when you made or took a call. I suppose you could DIY a relay to do that for anything you installed.

Jeremy

compu_85 · #10 08-05-2013, 01:51 PM

Quote:

Originally Posted by Jeremy5848

Bonus feature: the little dash speaker on the driver's side (part of the sound system, left or right side as the country requires) has two voice coils. This speaker was used with the optional cellular telephone, hence the second voice coil. A nifty mod by M-B, most folks don't even know it exists. The second voice coil can be connected to any monophonic sound source -- a scanner, ham radio, or hands-free cellular system.

Jeremy

So that's how the cell phone worked! That's a bummer, I was hoping there was an input on the tuner. The phone mute is a simple input, just ground the mute pin on the back of the radio.

-J

Jeremy5848 · #11 08-05-2013, 02:47 PM

Quote:

Originally Posted by compu_85

So that's how the cell phone worked! That's a bummer, I was hoping there was an input on the tuner. The phone mute is a simple input, just ground the mute pin on the back of the radio.

-J

My thoughts align with yours -- I had always assumed the cellphone tied into the sound system and used its amplifiers. When I first saw the second voice coil (fortunately recognizing it for what it was) it took awhile to figure out the application. I can't remember if the pre-wiring that Mercedes did for the cellphone function extended to wiring the speaker and if so, I definitely don't know where the wire leads to. Only the elves know!

Thanks for the explanation of the mute function; that would be an easy mod if I ever get around to installing amateur radio in the car.

Jeremy

Zulfiqar · #12 08-06-2013, 08:53 AM

i'll check - most probably the wire for the second coil ends up in the phone connector in the trunk, The antenna also has the extra "fon" port on its amp (whose pin I borrowed to repair the main trigger pin to raise the antenna).

I can bet the mute function is also in that serial connector

jay_bob · #13 08-06-2013, 10:11 PM

On the Becker 1692 you ground pin 3 on the A connector to get the radio to mute. The LCD shows PHONE and if you are playing a tape or cd it pauses.

You should be able to adapt what I did on the W210 on the later 124s if you want to install a handsfree kit.

http://www.peachparts.com/shopforum/car-audio-multimedia/336476-analog-cell-phone-update-1998-w210.html

lorenztl · #14 03-10-2014, 12:47 AM

Excellent pictures and write up on the model 124 E300D door. I replaced the Vacuum Actuator in the drivers door today. The rain guard is like a rubix cube trying to reinstall it. Spent an hour trying to install with no success...whew! Your pictures are very helpful and I'll try again next weekend when I return home.
Your comments about the automatic climate control ring true. The Mercedes automatic climate control is horrible. A manual system would be much superior and would surely enhance a Mercedes resale. It is an awful ventilation system with many expensive problems...what an absolute disaster when those pods need replacement.
Thank you for this excellent write up!

gastropodus · #15 02-01-2015, 12:27 PM

Thank you for this pictorial write up. It matches much of what I see on my W201. I wonder if you could clear something up for me: I've been to the junkyard and have been unable to remove a drivers door lock. You mentioned that there is a clip that holds the outside part of a door handle to the door; I take it that working inside the door one has to slide a clip to release the outer portion of the doorhandle, is that right? Are there two clips, one for the pivot end and one for the cylinder end? Are there any other tricks you can pass on for removal of the entire lock assembly, including cylinder?

Thanks,

Kurt