I was wondering, why does mercedes use vacuum for the door locks and climate control systems when nearly every other car maker does not? Also does any other car maker use vacuum extensively like mercedes does? From what I have read here they seem to be unreliable. Thanks

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Adam,
1986 300E
1997 Acura Integra GS-R

It sucks :D :D :D. Seriously, I think one advantage to vacuum is that it's less expensive to engineer certain types of control systems. It may appear to be less reliable...but, the prime movers in a vacuum system are a lot less complicated than those similar components in an electrically actuated system. I personally like it because it doesn't catch fire when it shorts out, it's a lot easier to isolate individual components and test them...like I said before...it sucks...and overall it's been my experience that replacement costs are lower on vacuum systems..IMHO

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Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..

Over the past 15 years and well over half million miles of vacuum door lock usage, I have seen the systems to be ridiculously reliable. The few times that I have had a problem, it was extremely easy to troubleshoot, replace the part, and the part was very cheap both times.

Also, to use electrics on all doors plus the trunk and fuel filler that lock automatically when the driver locks his door would be a problem.

As a matter of fact, I was disappointed to see them go away from the vacuum system on the 203 car, the electric locks are noisy, the vacuum locks were absolutely silent.

Good luck,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

I have had no problems or complaints with my vacuum system. I find it a lot quieter and much more reliable than other systems on other cars I have owned. Anyways, if Mercedes started using different systems just because other cars do would you still want a Mercedes? All the little differences like this add up to make great cars.



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Jason Priest
1986 420SEL

I was just wondering that because I am not too fond of the vacuum door locks on my car, the delay from the time you unlock the drivers door to the time the passengers door unlocks get me a bunch of "unlock the door" comments from the passenger, also I went to best buy to look for a alarm system so I wouldnt have to lock the doors manually, well they told me I would still have to lock and unlock my doors manually because it is vacuum operated. And the reason I hate my climate control is it does its own thing all the time, for example if I turn the heat on in the morning it works just fine, but then when it gets to hot and I adjust to the white section of the knob it stays on full hot, then I just turn the knob from full hot to full cold a few times and it eventually works again, it does this quite often but I dont have the $$$ to get it fixed. Those are the reasons I dont like these vacuum systems.

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Adam,
1986 300E
1997 Acura Integra GS-R

Most Hondas and Chryslers have vacuum actuated AC controls so there's a lot of cars on the road with vacuum AC controls.

BMW manages to have electric locks and a locking fuel filler so that's not what prevents MB from 'moving on.'

With all the other electric controls on an MB door, a couple more wires and a solenoid for electric locks cannot be a big deal.

My issue with vacuum locks is that when rear seat passengers open a door when the system is locked, it feels like something is being forced to allow the door to open. Also, that door lock can't seem to decide whether to stay open or join the other in being locked when the door handle is released.

Sixto
78 450SEL
91 300SE

This is a simple and reliable system. It sounds like you have a minor leak you need to trace down and fix. A vacuum schematic and a handheld vacuum tester is all you need.

Show me a system like this that someone doesn't like, and I'll show you someone who does not understand the system. This one is easy to understand, just give it a chance.

Another advantage to the system is lack of weight.

Good luck,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Pezzy,

Go to some other shop regarding the remote door-lock opener because it is definitely do-able by your alarm system. I have a Sabre system in my car which has remote doorlock and remote starter included and works like a charm (I love the remote starter in the winter, set the A/C control to automatic heat, come out of the movies in 15F weather start the car up from inside the theatre and by the time I walk to it is blowing warm air). The car is same as yours. If you want you can also have your windows rolled up and the sunroof closed on remote locking but that will require an extra relay or two. And if your passengers can't wait a second or two well...
Tell them it is the price to pay to ride in a Benz. :-)

Alex

Pezzy,

Go to some other shop regarding the remote door-lock opener because it is definitely do-able by your alarm system. I have a Sabre system in my car which has remote doorlock and remote starter included and works like a charm (I love the remote starter in the winter, set the A/C control to automatic heat, come out of the movies in 15F weather start the car up from inside the theatre and by the time I walk to it is blowing warm air). The car is same as yours. If you want you can also have your windows rolled up and the sunroof closed on remote locking but that will require an extra relay or two. And if your passengers can't wait a second or two well...
Tell them it is the price to pay to ride in a Benz. :-)

Alex

remote starting itself is just cool. :) hehe the look on people's faces whent he car turns on is classic. more of a shock than anything else. :) ehehehe

Now if you had the windows roll up and down, then that would be cool, but watch out for that, it can be bothersome. many problems can go on with the window modules. the best thing to do with any aftermarket wiring/actuators is to water proof them. put them in bags, seal them with silicone, do what ya gotta do, because water can kill them easily if the window seals leak.

Alon

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'92 300CE
Metallic Black (Blue Flaked) on Parchment
Clear Corners
94-95 Tail-Lights
Debadged
Black Grille Insert
78.5k Miles

Future Upgrades:
Sportline Suspension
17" AMG Monoblocks or EVO II's
Euro Headlights
Performance Chip
AMG Exhaust
http://home.earthlink.net/~asherson/my92300ce.jpg
Click here to Go To My 300CE Page

I may be wrong here but I beleive '89 and up the window roll-up feature is incorporated into the factory doorlock. You just have to keep the key in the lock position for a second or two and wait until it rolls up the windows. In that case the relay is not even required for the aftermarket system.
Tell me if is so. Thanks.

Alex

At least our washer fluid spray is not hooked up to the air valve on the spare tire like my '71 Volkswagen, Features like that made me fall in love with German design. Every Cadillac my mom has owned has had the electric door locks fail. I think it is much easier to find a vacuum leak as opposed to a poor ground/bad switch/fuse/wire/etc....

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'79 300SD (340K),'71 VW Karmann Ghia conv.,Toyota '77/'88 Land Cruiser's