W202 flat battery quandry !

[mercman149]

Today I discovered the battery in my W202 C180 was completely flat and the boot lock was siezed so I cannot get into the battery to recharge it. :twisted:

Anyone got a solution?

Is there somewhere to jump it in the engine bay? That sort of thing.

Thanks

 

[bigasotonuk]

Hi,
Have a look under the bonnet, on the passenger side just to the rear of the top of the shock absorber you will find a small black box, remove the top of this you will find two electrical connections, one of these connections (which one can,t remember from memory but it can,t be hard to identify as I did it) you will need to put 12+ and the 12- to the chassis, with this connected you should be able to power up the car enough to be able unlock the boot with the boot release on the key or centre console switch.
Do not try to jump the car from this point.

 

[mercman149]

Charge via 12S towing socket?

The car is fitted with a 12S towing socket.

Could I trickle charge back through the permanently live supply?

 

[bigasotonuk]

I suppose you might be able to charge it through the 12S tow socket, but it would depend on exactly how it has been wired as some tow bar wiring can be routed through relays possibly even ECU(s) if its OEM wiring install.
But why would you go to the hassle of wiring a charger into a plug when you could just clip it on the connections under the bonnet that are already there, took me longer to run out the extension lead to plug the charger in to connect to the connections than it did to get the boot open.

 

[mercman149]

Central locking success - now the lock barrel

Connected battery charger as you described and after 1 hour the central locking worked and I was able to unlock the boot.
Dont know why it did not work yesterday!
Battery now on charge proper.

Now,any idea the best way to free a siezed lock barrel?
I have it soaking in WD40 at moment.

Thanks

 

[Frontstep]

The lock needs a good vibration with a penetrating fluid I stuck an old electric toothbrush end in with some for one I did.

WD40 collects muck don't forget to clean it out and dry it before applying a dry lubricant afterwards petrol or something similar.

 

[mercman149]

Lock barrel now working

Took lock to bits, sprayed barrel with penetrating fluid, gently and repeatedly tapped with hammer and one by one the lock 'tumblers' started to free themselves. Rub with a brass wire brush and barrel working again. Have washed it out with petrol and ordred graphite powder.
Lets just hope I can put it back together again once the powder arrives!
Thanks for the advice guys.

 

[mercman149]

Wet battery courier

On a similar sort of theme, anyone know of a courier company who will take a wet battery and not charge a 'kings ransom'?
I have one to return to Luton - 5 months old and not holding it's charge. Not good.