HELP! Mercedes Cl500 W215, Battery Draining very quick!

[jwhelancarpentry]

Hello there,

I am hoping i can (once again) pick your brains, to try and understand the problem my lovely Mercedes is showing!

I have a w215, CL500 2002. Brilliant car, absolute beauty.


However..

If for example i drive to my Mrs's house, ill park the car on the drive, come to start it in the morning, and nothing. Flat as a pancake.

It is obviously a very very big drain, to be able to flatten a battery of that size over night!? I have done the simple things: turn wipers, lights off of Auto. But now I'm lost. However, previous to this. When it went flat before. I had the trunk open, and i could hear a ticking/knocking noise from the left had side in the boot. However i have not explored this yet. I do not know what it could be!

Any help, ideas are always very much appreciated!

Regards,

Jim

 

[television]

Draining that fast it could be a faulty diode in the reg pack with leaky reverse current.

The seat controllers can give drains, not not that high and usually in the order of 200ma max

Please see
http://forums.mercedesclub.org.uk/showthread.php?t=79442

 

[Lexman8]

I had the trunk open, and i could hear a ticking/knocking noise from the left had side in the boot.

The pneumatic pump for the doors, etc, is behind the trim, top left in the boot. That's probably the source of the noise but whether it's the cause of the battery drain is another matter. Normally it would be a whirring/humming sound when running and usually only for a few seconds at a time.

In the attached pic it has 'MADE IN GERMANY' on the cover.

 

[jwhelancarpentry]

Forgot to mention

Hi there, thank you both, for your replies.

I forgot to mention, i am currently using a spare key, which is not a keyless entry one. The keyless entry warning sign, is forever coming up on the dash board. And sometimes, i have noticed the Mercedes dash board being illuminated, with the keyless go warning on the dash. Could that be the drain?!

Cheers lads,

Jim

 

[television]

Hi there, thank you both, for your replies.

I forgot to mention, i am currently using a spare key, which is not a keyless entry one. The keyless entry warning sign, is forever coming up on the dash board. And sometimes, i have noticed the Mercedes dash board being illuminated, with the keyless go warning on the dash. Could that be the drain?!

Cheers lads,

Jim

No, as the cluster all goes dead once the car is closed and locked,