W203 18amp battery drain

[Scruffman]

Hi all

I've a 2004 C220 Avantgarde, the battery was flat the other morning and with it been the original I pressumed it was bad so replaced it.
The new battery was dead within 5 hours!
I got out my my multi meter and discovered an 18amp drain when the car is complety swiched off and locked, I have tried pulling all fuses and relays one by one, none of which affected the drain.
I read that there maybe a coolant heater that could be sticking on that is located just above the starter motor, but I could not see it and I am not completly certain I have one, it is very difficult to see above the starter motor from above so I had to look in from below.
I guessing it can't be a short circuit as I would probably have a fire on my hands!
Any help from any of you guys with this would be very grateful.

Thanks in advance

 

[richard]

That is about 200watts so you should be able to find something getting hot.

Try feeling the alternator in-case the regulator has failed.

Richard

 

[Scruffman]

Thanks Richard, I'll get the battery hooked back up and see if it warms up

 

[Hawkwind]

Is there anything after-market fitted to the car?

If so, I would start there first.

The reason I ask is, I had a drain on my battery and it turned out to be the after-market stereo, which had developed a fault.

 

[Scruffman]

Hi

No, everything is original, I've had the car since it was 4 months old, it has the comand unit but I have pulled all the fuses and that made no difference. I'm going to reconnect a fully charged battery tomorrow and see if anything gets hot under the bonnet.

Thanks

Tom

 

[brucemillar]

Before you connect up your charged up battery. Check it is not draining on its own.

Sent from my iPhone using MBClub UK

 

[mersum1es]

Thats huge drain... if your would be diesel, it would have that electric coolant heater, gasoline engine has not. Breather hose has also heater in some models, it might be only norther country option. Drain is so big that in cannot be any other 'normal' consumer... I don't know if reg pack of alternator could draw it.

 

[Scruffman]

Hi Bruce

The battery is a brand new Bosch, lasted no more than 5 hours idle, the original was a Varta same result unfortunately

 

[Scruffman]

It is a diesel, I think I may have to dig a little deeper for that heater!

 

[Ted]

Richard has summed it up.
If it is draining 18 amps then something is getting so hot (200 watts) that you won't be able to miss it.
Highly unlikely to be inside the vehicle.

 

[mersum1es]

It is a diesel, I think I may have to dig a little deeper for that heater!

Ok, then its no 1 in the check list:

http://mercedes-benz-teile.info/Images/Imgs/BM_IMAGES_ARC/B20100000019.050810.png

 

[Scruffman]

Ok sorry for the update delay I've been away with work, I disconnected the coolant heater which dropped 16.5 amps, the seat module drivers side was pulling the remaining 1.5amps!
Thanks for all your help