Mercedes C220 Door Lock Vacum Pump, is my newest problem. I took my friends C230 pump to see if my wiring was fine, and the pump had different wiring, however it connected except my car wouldn't start, but it proved my wiring was fine. I was wondering if anyone else has had there door lock vacum pump fail on them? and wheather its caused driving problems for them...that's not a typo. My car's auto theft kicks in sometimes, and I can't start it. I have to lock all the doors with my key, wait a couple seconds, open driver door, and she starts. I'm surprised mercedes would link the pump with anti theft knowing its a part that might need repairs in the future. I was wondering if anyone knows anything about these vacum pumps? Has anyone worked on these pumps before or know how to fix them?

I've taken my air pump apart already, and noticed the board inside and everything. Nothing smells bad, and no signs point to circuit board burnage. I'm afriad to work on this pump however, since I'm unsure if I mess anything up, my car might never start again until i get a new pump, which mercedes canada quoted me in excess of 1200 dollars. I can't seem to find any used ones either. If anyone knows of any common problems or quick fixes for these door lock pumps, please let me know. Thanks.

Doesn't every mercedes have a vacum pump centeral locking system? and am i the only one to ever have it break down on me?

what specifically is the pump doing, or not doing? these units also supply supplimental vacuum to the climate control system, the main problem i have seen with your model is the climate control has a leak and this causes the pump to run excessively, over time if the leak is not fixed this will cause the pump unit to fail, is the central locking feature locking and un locking the doors? please let me know more about you specifin problems. you can send me an email if you want, to the address below.
Ray
mercedessd@cox.net

Hey thanks for the response. I had no idea that this unit was also incharge of supplying supplemental air to the air climate control system. Today I did notice however, that my passenger side vents were letting cool air come out while only the driver side was pumping out heat. I don't know if this is related to my Vacum pump however. Besides this problem, my air climate control system seems to be working fine. However my door locks don't work at all. I have to manually lock my doors by either pressing down or by getting outside and using the key. I can still roll all four of my windows up using the key, however it makes no effect on my door locks. They have simply stopped working. Also my car will not start up without the vacum, or if I have locked one door and unlocked another by hand, seems like some sort of anti theft type problems. When I connected a c230 pump, the door locks did work, but the car doesn't start. Also the pump was newer, from a 96 c230. After seeing that pump make my doors work fine, I don't know if I have or had a leak in my system. I remember for the last couple years, when my climate control/air was on in the car, I would always hear a buzzing sound near the back seat, at which time I had no idea this part exisited. I asked a mercedes tech, about the humming/buzzing noise, and I was simply told that there was an air intake in the back of the car for climate control. Recently I have been wondering my self why the buzzing stoped, as did my door locks. However I never suspected it to have any links to the Climate control since it was still working fine. Even my recent problem took the mercedes techs 2 hours to figure out, since my windows, all four still roll up and down fine from the driver side door lock with the car's keys. I don't know what happened to my vacum pump centeral door locking system. Is there any help you can provide me with? Thanks.

it does sound like the pump burned up due to a climate control system vacuum leak the pump will cycle too often and burn up the little pump motor inside, you might get it to wok again for a while by spraying some lubricant inside the pump area, does it run?, the 2 unfortunate parts of repairing the problem is for that model the two elements that usually cause this probem are so far into the dash that it has to be removed, and the second part is the price of the pump, usually close to a few thousand dollars, i guess you could get a new pump and disconnect and plug the climate control supplement vacuum line from the unit. what is the part number for your pump? bosch and mercedes if given? i will see what i can find.
Ray

what all does that pumps funtions cover? Engine? Door locks? AC?

"I'm surprised mercedes would link the pump with anti theft knowing its a part that might need repairs"

The central locking pump validates an authorized unlocking of the vehicle and disables/enables the starter lock-out relay, allowing the engine to be started.

You could test the motor by jumpering 12V to the appropriate leads on the motor connector - I would definately disconnect the motor first and do it on a bench. It the motor runs the problem is in the central locking control. As I recall, the pump should run for a few seconds when the doors are unlocked. The pump goes to a manafold located in the rear left fender area, then vacuum lines go to each door, trunk and gas door. You could block off those one at a time to see if any of them is causing problems.

I have had problems with dash vents due to a vacuum leak and with the door lock motor on my '96 c220 but they were unrelated and one did not cause trouble with the other. I had to have the dash removed and a bad vacuum servo something replaced in order for the dash vents to work properly - big job $1200. My door lock motor was cycling off and on every 10 sec or so and that was caused by a signal from the climate control "EC" switch. On that one I disconnected the EC wire from the connector on the lock motor and called it fixed.

Sorry - Not left, I meant right rear fender area near the pump. You could also test the pump by measuring the voltage at the connector while someone unlocks the door. I think it you should see 12 V for a few seconds. You will have to get I wiring diagram.

Thanks for the response. I tried to power it up, no response. I took it out and the car didn't start. I threw in a pump from a friend's C280 and it was different and didn't work. Sometimes If i lock the driver side door manually, it unlocks my rear door! so i wonder if their's air in the pipes still ??? i've had times where I lock the doors, come back and one of them will have unlocked. Its strange that by pressing down on a lock, the air moves and unlocks another lock. My mechanic was also quite shocked. Mostly my car's anti-theft doesn't kick in, but sometimes I have starting problems where it won't turn over until i step outside and unlock door locks. Do you think I still have a partially working pump?

thanks

Your car should start with the door lock pump removed. When I was having problems with my door lock pump, I left the pump disconnected so that it wouldn't burn up. The car started just fine. I used the key to unlock the drivers door and had to manually lock and unlock the other doors. As far as the pump goes, I think it is prety straightforward. When the pump runs the vacuum actvates and all the doors should either lock or unlock at the same time. It looks to me like you have two problems - one with the pump and the other with the central locking/anti theft system.

I had the vacuum pump making buzzing sounds till it got me very mad. It would go on as soon as I start my 1994 C180. The noise is from the back boot under the fuel entry pipe and thats where the pump sits. The only problem was the rear headrests won't drop when I press the button on the dash. After a very expensive pulling off of the dash, they found 2 plastic socket things with rubber fabric inside which were cracked and holed. These changed, the pump is quiet now, saved $1000 for replacement, rear headrests work now and fall quickly. However, my aircon now acts strange. When I accelerate, the compressor goes off, get hot air or no cold air. With the accelerator off or released, it comes on again. For one year the aircon worked correctly after the vacuum fix.

YEah, i took the pump out again today and tried to start the car. Didn't work at all, it was as if anti-theft engine kill was in effect. Does anyone know a pump rebuilder? or someone that's fixed one before? I took the pump apart. It looks very simply inside, a small chip board, casing and a dollar store motor. Doesn't seem very high tech. Does anyone know where i can get that motor from? thanks

I had also experienced starting problems on several occassion and came to the conclussion that if one does not close the door fully and locks the car with door not fully closed - upon return and unlocking the car- it will not start. The anti theft system had kicked in.
Then by unlocking and opening the door - and then closing fully and locking it again and then unlocking it - it will start.

I hope it helps someone

nagy1106

Yes this is true. I had some of these problems, and shortly after, my pump went. Now it does it everytime anything manual besides using key is done on my ex-power locks. The security system is tied into this motor system.

anyone figured out how to fix one yet??

__________________
My Cars
Mercedes CLS
Mercedes C-Class W203 - All time favorite

R.I.P.
Mercedes C-Class - W202 Lemon
Mercedes ML - Warrior
VW Jetta – Worst Car I ever owned - Alot of problems