Dead Battery

[tolly]

Hi Guys
In a spot of bother :-(
I own a W202 C180. My battery went dead and I cant open the boot with the key.
Is there any other way to perhaps start the car or get access to the battery??
Please help :-(

 

[Mercsys]

You may have jumper points under the bonet, or you could jump directly to the starter, but be carefull.

 

[tolly]

I was thinking about going direct to the starter but that will spin just the starter wouldnt it?? I mean theres gonna be no spark or is there?

And any idea what the jumper points might look like or whereabouts??

 

[stevesey]

I was thinking about going direct to the starter but that will spin just the starter wouldnt it?? I mean theres gonna be no spark or is there?

Go to the battery side of the solenoid and you will be fine. Also check the black box on the passenger side at the back of the bonnet for a suitable 12V point.

Have you tried WD-40 on the lock yet - with patience they often free up. Might take plently of soaking and jiggling with the key blade though.

Once you sort the battery - sort the lock out as well for next time (and grease it check it every 6 months). Yours is a very common situation - no one every uses the key until the battery goes, by then lock has seized up.

 

[Mercsys]

My jumper points are a brass earthing tube/stud thing and a positive point under a plastic cover with a + in a circle if I remember, just in from the wing ahead of the firewall. Do not run the other vehicle when they are connected.

If you have to jump to the starter +, go to the heavy bolt + point, this should be a direct connection cabled to the battery. But then you will only want to open the boot?

 

[Mercsys]

Never have/put the key in the ignition if you are charging the battery!!!

 

[tolly]

I have no plans to start it as of yet. Just want to get access to the boot so I can charge the battery or replace if necessary. Shes been parked up since September last and with the winter and all the battery packed in.
Also about the WD40, yes I used and plenty ;-) My key is small bit bent so it doesnt go in all the way. Have to get a new one done up. Thanks for the help lads, ill let ye know tomorow how I got on

 

[jefrs]

Whilst it is better to charge straight onto the battery, you /can/ charge onto the terminals in the engine bay. The terminals are there for jump-starting the engine.

Once you have connected a charger, battery or another vehicle to the engine bay terminals, you should be able to unlock the boot. Problem with a charger is a small one may not have enough go in it to power up the systems but most will power up the first key position to unlock the boot (don't try the windows until the battery holds enough charge). Some chargers can be used for jump-starting, these are ok to switch on the ignition and start up.

Please do not use WD40 on a lock, it is a de-watering solvent and will wash all the lubricant out of the mechanism. It is not a lubricant.

You can squirt some 3-in-1 into it but this can air-harden into a gum, better to use a proper lubrication oil such as SAE30 (lawnmower) or even chain saw oil, from a can. A decent oil for "fishing reels" comes in a little clear tube with a handy "hypodermic" tube, got some in Halfords.

Do you know why your battery is flat? - you may need a new one, and it is a jolly good idea to check all the earth points (mainly engine bay) for corrosion and poor contact (electrical connections do corrode very easily).

 

[tolly]

My merc was made in Sweden. No rust in that baby
My battery went dead over the harsh winter.
I opened my boot by connecting up another car to the terminals and twisting the key...
Thats all I wanted, not gonna start anything until I know where Im going with the car

Thanks for the imput guys

 

[jefrs]

Electricity through different metals plus a little moisture equals instant corrosion. Oxide is not a good conductor. Earth connections do go off, even on Swedish steel. I did have a Volvo 245 tank.