I am constantly amazed, if you run down the battery why not call Mercedes for their lifetime "Road Assist" 1800 FOR MERCEDES, FREE JUMP, BATTERY AT OVER THE COUNTER PRICE, TIRE CHANGE AND FUEL.

Peter,

It would seem to be that simple, but the problem is the trunk is locked and tumbler to the trunk lock cylinder is inoperable. There is therefore no access (even for roadside assistance) to get to the battery to jump the car.

There is an electric pump that makes the vacuum to unlock the doors and trunk, but the battery is too dead to operate the vacuum pump.


Air Jordan,

Get a basic charger from Wal-Mart, or an auto supply.
Connect the positive lead to the wire Arthur pointed out.
Connect the negative to any metal ground point on the car.
Don't try to jump start the car from under the hood!
Leave the ignition switch off while charging the battery.
Do not use a charger that plugs into the cigar lighter on your Mercedes.

Charge the battery until there is enough power to operate the vacuum pump.
Use the ignition key in the door to lock, then unlock the car using the vacuum system.

Once the vacuum system unlocks the car you can push the button and open the trunk.
Once you have access to the battery you can replace it or jump-start the car and take it somewhere to get a battery.

You are almost there!

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02 S500
92 500SL
92 400E (Sold)
87 300E (Sold)
83 300D Turbo (Sold)
75 300D (Sold)
74 240D (Sold after 20 years)

thanks speace and arthur

sorry if i sound a bit lost but im a bit anxious cause I reaally want to get the trunk open before my dad calls AAA to fix the problem as there are some "fraternity supplies" that I don't want him to see....

I did pick up the cigarette charger but did not decide to switch on the ignition so I'll probably return it. After work though I'll go to Kragen or Pepboys and pick up a trickle/home charger and then connect it to the terminal I pointed at in the picture ( right? ). I just want to be absolutely sure or else my dad will get involved and call triple a and I'd be dead

Ah - the truth comes out. I'm sure the initial assertion, that you didn't want to miss school, was at least a partial truth.

Smokin' type???

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A Dalton

lol i was for a little bit but i stopped cold turkey and it's been 3 solid months...it's mostly just cans and bottles in there

Well that's innocent enough.
I thought you were going to say bras, panties, " tire repair kits ", etc.

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2007 C 230 Sport.

It is that simple, the MB tech probably knows where he can apply 12 DC to get the PSE to run and unlock the car.
The other option you have heard is the cigarette lighter charger and turn on the ignition to backfeed the power.

It's better to say nothing and appear to be an idiot, than to post, and prove it.
It's what I get for posting about something I don't know much about. I shall try to be more discriminate in future posts.

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D

L,
Don't stop posting for fear of a couple of mistakes..this is a learning Forum..and I have seen you write some very good and technical remedies for fellow Benzers...
..if a posting gets corrected , it is not in disrespect ...it is for the sake of the Forum members and to help assure accuracy of the Archieves [which is where all this stuff winds up, unedited] for future posters and info searchers

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A Dalton

OK...I know im being real annoying about this but I bought the trickle charger today and just need the green light before I do this tonight. I don't want to mess up my car like I would have with the cigarette charger. It's just weird because that terminal has two thick wires

The first picture shows how I would set it up and the second picture is of the actual trickle charger.

Attached Thumbnails

   

Yes, you have it! You could even have gotten a larger charger, say 8 - 10 amps, for quicker charging. But that one should do it overnight, if nothing is on. Just connect the red wire either under the nut you have chosen, or either of the two to the right of it. (If you look closely, you will be able to see that all three of those terminals are connected by a buss under the wire connections.) Then connect your black terminal to a convenient ground point and you should be good to go.
Good luck with it,

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Richard Wooldridge
'01 ML320
'82 300D 4.3L V6/T700R4 conversion
'82 380SL, '86 560SL engine/trans. installed
'79 450SL, digital servo update
'75 280C

....to add to Richards instuctions, be sure that all devices and key is OFF when using that charger, since it is so small, you need all the power it can supply to go to the battery and not have the drain factor of any other stuff...
Once you can access the trunk , you are going to want to give the battery a good change with a larger charger [ if the battery is any good]

*EDIT note*

Sorry Richard..just noticed your post did mention everything OFF.....

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A Dalton

Alright thanks guys for all the help. I'm gonna go do take care of it right now, wish me luck!

The battery is only 6 months old, I think it's my alternator that drained the battery overnight.

AJ, the alternator wouldn't drain the battery ... it recharges the battery when the engine is running. Check the condition of the voltage regulator brushes. (The voltage regulator attaches to the back of the alternator with two phillips head screws.) If the brushes are worn down to short stubs it's likely the voltage regulator isn't recharging the battery properly. The brushes on a new voltage regulator are approximately 3/4" long.

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Fred Hoelzle