OK, I searched through the archives for some support on the door alarm system, but found nothing. Before it got really cold here, I saw a clue as to some potential failure issues. I noticed that when locking the car, the driver's door is the last to lock (and unlock), by a noticeable margin. Now that it's really cold here, when unlocking the car, the alarm goes off and putting the key back in and locking it back and unlocking (in any combination) has no effect (today).

I now have to unlock the car from the passenger's side, while the neighbors look on for more horn noise from the SOB. I figure these door locks have to be on some vacuum activator system-each door with its own proprietary release and lock? If it's just going into the driver's door-cool. If it's hunting for some accumulator or something in the dash, not cool.

I know someone here has been done this road?

*Update:1/4/09-installed new battery, no fix. Only way to deal with this in the bitter cold, is to unlock the passenger door then go around and enter through the driver's door. I can hear all the locks working, but something in the driver's door triggers the alarm. If it's not super cold, another turn open on the driver's door kills the alarm. Bitter cold; no way I can shut off the alarm from the driver's door.

1/3/09 I did finally find some threads on the door lock system, but mostly for W140 & 220 models. There is repeated mention of a PSE pump and a 'closing assist' pump. One thread talks about a pump under the carpet, under the rear bench, on the right side for the W124. In almost all these posts however, the problem is a door (or doors) that don't latch. Mine all latch fine (even the back door hatch)...it's the driver's that is not unlocking completely and causing the alarm to go off (I think). New theory; I could have a faulty battery, because this all started after my headlights were left on. I'll check the battery output while running.
Kevin

 

What year and model?

 

Uhhh...it used to say on the left what I had-maybe that's another forum. Sorry about that- '92 300TE 4matic.

Kevin

 

It sounds like you might have two problems. As for the alarm sounding when you unlock the car from the drivers door, I would look into the micro switches in the lock. The micro switches are what arm and disarm the alarm depending on which way you turn the key, they are known to wear out. Having keyless entry saves them as you no longer are using the key in the lock tumbler which wears down the micro switches.

As for the drivers door being slow to unlock, does this happen when you unlock from the passenger door? I would think that if you unlock it from the drivers side it would be the first to unlock since you are using the key to physically open the lock. If it is only acting slow when you unlock from the passenger side or trunk I would look for vacuum leaks in the yellow tubing that runs from the vacuum pump, under the rear seat, to all the vacuum actuators that are in the doors. Or the drivers actuator itself has a hole in its diaphragm, if that's the case replace the drivers actuator.

By the way we don't have a PSE or closing assist pump. The PSE is what the newer cars have, it combines the door lock vacuum pump, alarm and a few other functions into one unit. We also don't have a closing assist pump, that device allows the S-Class doors to latch themselves.

 

Thanks...and I gathered that in the threads-that we don't have a PSE or closing assist pump...but we do have some sort of device under the bench seat on the right side?

Well about the driver's door...for as long as I can remember, it unlocks and locks slower than the rest of the doors. I just always assumed that something wasn't 'equal', but everything locks and unlocks within two seconds. I favor your micro switch suggestion, as the bad weather here could have exacerbated that problem. I was having some trouble earlier in the season with the key/lock, but it was with the door & ignition as well. I wonder if just a new key might solve anything?

I'd have to check for sure, but I think even using the passenger side lock, the driver's door lock is last to close.

Kevin
'92 300TE 4matic

 

Having the same issues myself right now. I shall favorite this because this is going to save me from putting my fist through my window because it was starting to wear on me..

 

Bro....you're singing to the choir here. Which issue are you having, because I'm having three concurrent issues?

Kevin
'92 300TE 4matic

 

i concur with the microswitch... if the alarm was buggered then it would have similar issues when you unlocked from the passenger side or tailgate, so the alarm is probably okay, which narrows it down to the driver's door, and so probably the switch

 

Yeah, I had the door panel off when I put in the new sound system. That's not a problem for removal. There's only a few cut-outs here and there in the metal door framing though, hopefully enough to get at the micro switch. I can pretty much rule out the vacuum part of the mechanism now, because the door unlocks fine. I didn't know about the micro switch. Worse case scenario, I unplug the alarm-I can live with that for the winter.

 

I know that the doors/trunk all lock at different rates and that doesn't bother me, I consider it part of the charm of having a steampunk-esque benz :P

The issue I am having is the driver-side door unlocks but triggers the alarm issue which leaves me to either go to the passegner door or to the trunk.

 

Then you best bet would be to look into the micro switches.

 

That sounds exactly the same as my issue-micro switch and a known problem apparently with MB. Also, my key is not working that well in the driver's door and the ignition. Since both have been used extensively over high mileage, the ignition switch at least has to be changed out very soon. I've read horrific accounts of the ignition lock freezing and what had to be done after. The door lock is bad as well, since most normal owners enter in that way.;-) I don't know what all this is going to mean with matching keys etc.....my passenger door works fine... probably because it's not had near the wear of the driver's door lock and ignition lock....the trunk lock even less.