crescens

I have an old 2001 c-class. It’s been unused for the past months (in cold weather 🥶&#128584.
Now I can’t get into the car! Battery is dead. Manual key doesn’t work. What can I do? 😅
Thank you.

slammer111

What do you mean the manual key doesn't work?

Without being able to access or jump the car battery, you're looking at jimmying the door open or smashing a window.

TEAsE550

Happened to me once on my 2000 CLK430. I got in thru the trunk.

slammer111

^ That would work if the sedan has some kind of handle for folding the seats from the trunk, and if his trunk can be manually unlocked. Remember his car battery is dead.

TEAsE550

^ There was no need to use the seat release handles that are in the trunk to fold the seats forward. The trunk manual lock was the only lock that worked. I just got the trunk opened and put a battery charger on the battery in the trunk. 20 mins of charge and the key-fob opened the doors and the car started.

slammer111

The 2001 C class may have a manual trunk lock for the sedan, though OP mentioned his manual key doesn't work.

MB removed the manual hatch locks for the coupe in MY2003, so I assume this would also be the case for the sedan trunks.

The W203 battery is under the hood and not the trunk, so your solution wouldn't work.

TEAsE550

LOL....I just assumed it was in the trunk. Where's a car thief when ya need one ??

tjts1

You can jack up the car and connect another battery to the B+ terminal on the back of the alternator.

crescens

I don’t have any way of entering the trunk, there’s only the drivers door that can be opened with the key. And that doesn’t work, I can’t turn the key 😱
Thanks for the replies so far.
Any ideas? 😅

slammer111

The part of the handle with the keyhole doesn’t quite line up. Guessing someone replaced the tumbler in the past with one from another car. You may want to get that fixed at the dealer.

There may be a keyhole next to the trunk handle. They were installed on the earlier build coupes at least. Dip your head and look upwards.

Otherwise you’re looking at connecting to the starter cable or the brick method.

crescens

I have used the key a couple of months ago. How do I connect the starter cable without access to the battery?

slammer111

Starter motor is accessible from underneath the engine. Basically you'll be using the terminals as a jump point instead of the battery terminals.

In theory it should work since the starter draws a high amount of current. However I don't have information on which exact wires to use. You're trying to charge the battery, not crank the engine. Basically you'll need to disconnect the positive and negative wires (unless there is enough room to attach a thick enough jumper cable) to the motor and add a 12VDC power source there, possibly from another car or a battery of some sort.

tjts1

Jack up the car.

Donald McPherso

Wouldn't need that much power. If you can connect a charger from underneath the draw power might be enough to open the door. If not just leave it to charge and you should be good to go.

slammer111

On that note, how did your physical key stop working if it worked before?

I'd also try spraying some silicone lube into the tumbler.