Hey guys,

I have a 1992 Mercedes 400E and as I got in the driver's seat I was greeted by a dead battery. Lights, seats, everything is dead. Well I thought I could jumpstart the car, however since the battery is completely dead the vacuum system won't open the trunk where the battery is located. Also the lock on the trunk is also broken so I can't use the keys to open the trunk from the back.

What do it do? My dad is trying to call a locksmith. Is there any way to jumpstart the car from the front instead of using the battery in the trunk?

This is pretty urgent cause I have school tomorrow, any help will be greatly appreciated!

Dead battery or inoperable vacuum system shouldn't have any impact on opening the trunk. Have you tried turning the key 180 degrees and pushing the trunk button?

Thanks for the prompt reply

Well we got the car for free from a friend and since then the key never fit into the trunk lock...we think that either there's something stuck in there or the trunk lock is different from the door lock, which I highly doubt

No comprende. So this means you've never been in the trunk, or you're saying it's locked and you used to be able to unlock it from the doors - when the battery worked.

yea exactly the only way would unlock the trunk was from the doors - when the battery worked

Hook up a trickle charger through a circuit 30 fuse under the hood.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Should be a Pos jumper terminal under the hood.

__________________
A Dalton

Thanks for the suggestions!

@stevebfl
How would I go about doing that?


Would you guys know where the positive terminal is under the hood? I attached a picture of the engine if you guys can point out the general area where it's located

Attached Thumbnails

 

I don't think there is a positive terminal in the engine compartment. But you could check your owner's manual under jump start to see if it's mentioned.

Right behind the right side shock tower there are a couple of ground wires
[ W/10]. Just behind them is a 6 section terminal block. { X/10-4.]

That is power distribution from the battery POS.
Go to terminal #1 [ that is direct feed Battery circuit #30 SB mentions]
Hook charger pos there and neg on block or W/10 and that will allow you to charge the battery in the trunk.

Don't ask for physical appearance b/c I am working off your chassis 124.034 schematic.

__________________
A Dalton

Not knowable about this car, so this might be a dumb question. Why can't you just jump the car but putting the positive of jumper cable or charger to the positive on starter from under the car and the negative on the frame or other good ground?

Not a dumb question...just no need to get under the car b/c that jumper terminal is at the power distribution strip beghng the shock tower.

..but that would also work if one did not have the terminal set-up already Factory there ........

__________________
A Dalton

Wow Arthur thanks for the detailed explanation. I barely know anything about cars but I think we'reheading in the right direction. Here is a picture of the right (from the driver's perspective right?) side. Do you think you can point out what I should connect the positive wire to? Thanks thanks thanks

Attached Thumbnails

 

Lift up that blue outlined cover, and you will find several holes. One of these will give you + and another one -

Attached Thumbnails

 

__________________
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

Ok I see the holes but how on earth do I connect such small holes to my jumper cables to my dad's car??

thank thanks thanks you guys are saving me a bunch of money