Awhile back I had a customer come in with a complaint that his door locks, convertible top and soft close trunk were not working on his 2005 Mercedes Benz R230 SL500.
Upon inspection of the fuses there were none blown. I then checked out his soft close / release actuators in the trunk, which also appeared to be okay. Finally I was able to get into the computer with an updated scanner but this was of no help either.
Where I ended up was the vacuum pump. Now anyone who has worked on Mercedes knows that they use vacuum to control the door locks, and on models from 1991 and earlier this vacuum pump use to consist of a single line. Well on the newer R230's with the retractable hard top they have about 8! Not only that the pump is 3X the size and if that were not enough the damn thing retails for $1200, although we were able to find one for a mere $600 LOL.
Anyway, upon inspection of the Vaccum pump I ran straight power to the motor and found it to be working just fine, which unfortunatly means the control board is bad, which will require you to buy the engine module / vacuum pump. The vacuum pump is located in the trunk off to the left drivers side. You will need to remove the carpet and foam to access the hydrolic pump that runs the retractible hard top pump. Once you have access to the hydrolic pump you will need to remove the four bolts that holds that down. Under that you will find another foam panel, and then finally the Vacuum pump and module. Be sure not to disconnect any of the hydrolic lines to the pump for the retractible top as you can just move it to the side.
Okay, now that you seen enough photos of the car so you know its the same as yours, start by checking the fuses. They are located in the rear passengers side glove box.
Open the glove box and remove the panel. You can hardly tell it's there, but it is.
Check all these fuses. If they are all okay then it's a good chance your vacuum module is shot.
Go to the trunk. Open it. You should have a small key in the transponder (door lock key fob) use this to open the trunk manually. Pull all the carpet out until you see the spare tire like above.
Pull the foam out on the left driver side to expose the hydrolic pump for the retractable hard top. THIS IS NOT THE VACCUM PUMP. DON'T REMOVE THE LINES! Just the 4 nuts that hold the bracket down.
When the nuts are removed GENTLY slide the pump over. You will then have to remove more foam/sound proofing to gain access to the vacuum pump module.
See all them yellow lines? Them are the vaccum lines and they are attached to the vacuum pump. Dont do what I did and remove all the lines one by one, rather the grey plastic part is removable and will come off with all the lines in tact, this makes re-install WAY easier, but lucky for me I took pictures before removing them so I was able to get them back in the right spot. With the lines removed, disconnect the wires, there should be two bulk heads. Remove the pump, take apart and run power (12 V) to the pump. If the pump spins you know the board is shot. Bend over and take it in the can for at least $600 but WTF you own a $140,000 car so that should be nothing.
Now, send me a nice fat tip for helping you save $2000 which the delalership would have charged you. LOL Just kidding... Well maybe not, but at least a "Hey thanks that fixed my car" would be nice.
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What is to give light must endure burning -- Viktor Frankl
Great thread SELLC ! Now all I need is 140 K to grab an SL & then wait for the problems to start !
Rastus
__________________
"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together". Dwight D.Eisenhower.
Thanks for the concise instructions. Are you saying that the door locks and the retractable top are both run by the same vacuum pump? I.E. my door locks work fine, but the top will not fully open. The trunk lid opens up, the roof appears to unlatch, but that's as far as it gets. The hydraulics seem to be whirling away. Could it still be the pump? Or some other issue I should be looking at. My apologies for the year old thread bump.
Your issue sounds more pump related. Usually when this part goes bad you wont have any noise at all. The power door locks will not work, nor will the soft touch / auto trunk button.
I didn't get into the pump, but I'd imagine that's where you will have to start.
__________________
What is to give light must endure burning -- Viktor Frankl
i have a VERY similar problem. it started out as a trunk issue and then it was the driver side that wouldn't lock so i forced it in i forced it to lock but then the next day car wouldn't unlock!
i finally got the lock smith to open my door
so
i can lock the car now but it doesn't lock if that makes any sense so if you try to open the alarm goes off.
my manual key doesn't work for the driver side. (however it worked for the trunk that's how i got the trunk to open)
is it a vacuum pump issue then?
what about the fuses? can you take the fuses out when the car is not running? or do i have to know which fuse it is to pull????
-- Edited by mercedessl on Saturday 29th of December 2018 08:40:44 AM
-- Edited by mercedessl on Saturday 29th of December 2018 08:41:51 AM
Carefully re-read the opening paragraphs in the original post sir.
It's easier IMO to test fuses across themselves with a multi-meter set on ohms. No power is needed, & look for 0.000 reading if ok. Fuses can be a real PITA to remove & visually check.
On the earlier designed cars from MB, the engine itself was the vacuum-pump, & there was a reservoir-tank that held the vacuum, enough to open the doors etc etc even after days of not having the engine running. Any how, for these cars, it was often the master-control-valve, on the drivers side door that was faulty, as its internal seal would wear & by-pass, hence your doors would stay locked, or move to 1/2-way position, or your fuel-door would open but the trunk would stay locked etc etc.
Do all the tests in the original post first. You need to determine whether the vacuum-pump is working.
Cheers,
Rastus
__________________
"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together". Dwight D.Eisenhower.
i have checked all the fuses and there is one fuse the 20A controls the centeral locking system i was able to get the locking system back for a little bit but now every fuse i use gets burnt after shoving it in that slot. it's the 20amp fuse i know what you are talking about. but what do you think? replace the vacuum pump? the PSE pump? please help
-- Edited by mercedessl on Wednesday 30th of January 2019 06:27:08 PM
-- Edited by mercedessl on Wednesday 30th of January 2019 06:28:24 PM
Since you are seeking help from us here, IMO, you're best to take it into a MB dealer, or recommended Auto Electrician, to keep everything safe.
Do not replace the blown fuse with a new one, leave it out.
Explain your circumstance, & work you've done so far to the repair people.
( A short-circuit in this instance, means every piece of wire in the circuit becomes a lighted-fuse, ready to ignite into fire. Your fuses blowing are stopping this for the moment. If you keep going on by your self, you're making matters worse, risking losing the car through fire & more expense in the end ).
Ciao,
Rastus
__________________
"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together". Dwight D.Eisenhower.
Sounds like the pumps are puckered up causing the short. You could unplug the pump unit from power (harness plug to unit), then re-insert another new fuse and if it does not pop then the wiring is likely fine and it's the pump unit - as shown in the photos.
If the fuse does pop, even after the pump unit is unplugged then you have a short, either from a prior accident or rodent but you will have to trace the wires at that point to find it.
If you're not mechanically inclined or uncomfortable with the process you could take it to the dealer or independent who will work on a Mercedes. If you do end up taking it in don't even bother telling them anything outside of what is wrong as they will figure it out and most likely tell you that a new vacuum pump unit is needed and make the repair. If you are in Michigan close to my area you could bring it to us also.
Good luck!
__________________
What is to give light must endure burning -- Viktor Frankl
Since you are seeking help from us here, IMO, you're best to take it into a MB dealer, or recommended Auto Electrician, to keep everything safe.
Do not replace the blown fuse with a new one, leave it out.
Explain your circumstance, & work you've done so far to the repair people.
( A short-circuit in this instance, means every piece of wire in the circuit becomes a lighted-fuse, ready to ignite into fire. Your fuses blowing are stopping this for the moment. If you keep going on by your self, you're making matters worse, risking losing the car through fire & more expense in the end ).
Ciao,
Rastus
Yo Mate, ever see the "potshumus Darwin award" where the guy replaced a fuse with a 22 shell? Didn't end well but he got the award.
Sounds like the pumps are puckered up causing the short. You could unplug the pump unit from power (harness plug to unit), then re-insert another new fuse and if it does not pop then the wiring is likely fine and it's the pump unit - as shown in the photos.
If the fuse does pop, even after the pump unit is unplugged then you have a short, either from a prior accident or rodent but you will have to trace the wires at that point to find it.
If you're not mechanically inclined or uncomfortable with the process you could take it to the dealer or independent who will work on a Mercedes. If you do end up taking it in don't even bother telling them anything outside of what is wrong as they will figure it out and most likely tell you that a new vacuum pump unit is needed and make the repair. If you are in Michigan close to my area you could bring it to us also.
Good luck!
so i got it replaced with a working vacuum pump. everything seems to be working. but the trunk latch is having issues. could this blow up the vacuum pump again if it's not taken care of? i remember this all started with the trunk not opening at first.
-- Edited by mercedessl on Sunday 10th of February 2019 11:34:21 PM
Take it back to the repairer, & explain the trunk issue...You may have a leak there, & an activation unit may need to be replaced...As the seasons change, moisture in the air can over time allow water to condense in a component, causing its operation to fail.
It may just need a clean-out / blow-out, or a diaphragm has ruptured meaning it needs replacement.
Should be an easy repair, as you already know what component is not working as it should.
__________________
"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together". Dwight D.Eisenhower.
Take it back to the repairer, & explain the trunk issue...You may have a leak there, & an activation unit may need to be replaced...As the seasons change, moisture in the air can over time allow water to condense in a component, causing its operation to fail.
It may just need a clean-out / blow-out, or a diaphragm has ruptured meaning it needs replacement.
Should be an easy repair, as you already know what component is not working as it should.
that would be me. i just swapped the tubes. that's all i did.
but as soon as i did that everything started to work and then the trunk started this continuous hissing and woudn't shut up. how about i replace the latch? they sell these Trunk Latch Actuators on ebay for $60 and they sell like candy
-- Edited by mercedessl on Sunday 10th of February 2019 11:37:56 PM
"Only an alert & knowledgeable citizenry can compel the proper meshing of the huge industrial & military machinery of defense with our peaceful methods & goals, so that security & liberty may prosper together". Dwight D.Eisenhower.
