C 220 CDI Battery draining

[JJMMCC]

Hi People,

Glad to have found this forum.
This is the first Merc that I have owned.
Great car but talk about information overload on driving the thing, me wee brains having to get used to all the info & gismos on the car.

However The only? Problem I have with the car is that the new battery will only keep its charge for around 1-½ days then is completely flat.
On looking into this forum I followed the following suggestion.
I have uncoupled both driver & passengers seat control modules but this has not stopped the battery drain.

To preserve the battery I first switch off the ignition & remove the key.
Pull the bonnet catch.
Press the keyfob unlock door button, then disconnect the battery’s earth terminal.
I then manually lock all the doors.

At present the car is not showing any errors on start up.

I don’t know if this is a wise thing to do as I’ve read horror stories of the W203
destroying SAM modules and other woes.

Any help would be appreciated.

 

[colechelle]

welcome!

First of all stop disconnecting the battery, i did a write up in diy on rear sams blowing when reconnecting batterys, you need a muti-meter connected in line with the battery, then in turn is to pull each and every fuse from the rear sam front sam and dash untill you get a reading of about 00.06ma, i would start with the four 20amp fuses in the top of the dash fuse box, they are your seat/door control module fuses, after trying that i would head for the rear sam, has the car got command???

 

[JJMMCC]

230 battery draining

Hi Colechelle,

Thanks for your quick reply.
Battery change seems kinda scary, for al MB’s technology the 230 seems a bit sensitive unless it’s a form of extra anti theft protection, at the cost of vulnerable SAM’s modules?
I will certainly do as you advise and work on the fuse route with an ammeter.

A point on the jump-starting as a last resort, would it be ok to jump with a standalone battery. I.e.: the other car not running during the jump start, the Mercedes starts very quickly after the pre-heat light goes out I don’t know if the jump would draw so much current as to totally flatten the other cars battery.
P.S.
Maybe that’s what friends are for.

 

[JJMMCC]

203 Battery draining

Hi People,
Following Colechelle’s advice I have systematically removed the fuses from the Front dash fuse box, Front SAM module, Rear SAM module.

I have even fully removed the SAM’s fuses and relays completely
I still have a large current drain.

My car does not have the command option.

My thoughts are could it possibly be the alternator ?
Any help would be appreciated.

 

[colechelle]

the other fault that is common is the heater in the water jacket, that pulls about 18amps and isnt on the fuse side, its under the inlet manifold, main feed of the battery stright to it, not easy to get to but the only other thing i can think of!!! rear of the engine above starter , try disconnecting that!!!

 

[hmang]

how large is your current drain

i dont think your bat would last 1 1/2 days with a constant 18 amp load

 

[Dec]

My thoughts are could it possibly be the alternator ?
Any help would be appreciated.

It might be wise to buy a Volt Meter that plugs into cigar lighter, it will give you an indication of how your alternator is performing as you drive and the state of the battery before you start car, not precisely accurate but a good insight as to how your battery is performing while you drive.

Dec

 

[JJMMCC]

Sorry for the late reply to your suggestions, can only work on the car inbetween bad weather.

At present I cant find any sign of a water jacket heater.
I have totally disconnected my alternator and am still getting the current drain, MB what a crap place to put an alternator.

I’m using a analogue multimeter with an 8 amp shunt and the meter is indicating 2 amps
So my drain is around 10 amps

 

[Dec]

How many volts is the alternator producing at the battery with the engine running?

Dec

 

[colechelle]

10 amp drain,have you any phone kits, sat nav wired in to the car anywhere? also have you unpluged the relays one by one, water heater you will only get to under the car and putting you hand up above the starter motor, no other way of disconnecting it, still placing my money there as i have replaced so many of them now!

 

[miko666]

Battery Drain

I have recently had the same problem except that the battery drained in a couple of hours, this included a brand new Bosch battery. I had to have my car jump started 3 times. I took it to the garage where I bought it from and they had it for 3 days and gave up. They passed it on to an Auto spark who diagnosed a dead short in the water heater jacket. I have not had the work done yet but I will post as soon as I have, the diagnosis may help somebody

 

[television]

Hi miko,, is your the same car

 

[Xtractorfan]

I think cole has mentioned the water heater twice already...

 

[miko666]

Yes its an 05 plate, I have only had it 2 and half months. I love the car but my wife thinks I need to be pyschic as I should have forseen the problem. I can only hope that this is just a glitch. As a matter of interest does anyone know how much these things cost?

 

[television]

Yes its an 05 plate, I have only had it 2 and half months. I love the car but my wife thinks I need to be pyschic as I should have forseen the problem. I can only hope that this is just a glitch

Well you know that she is rightIt did not help me when I part exchanged my early ones, the new ones were all right as well

 

[miko666]

Battery draining.

I suppose if I did have foresight then I would have had a Mercedes a lot earlier and not a wife.
I dont think it is the battery thats being drained by dead short its me by my dead short wife (shes only 5ft lol). Well anyway the Merc beats the Laguna I swapped it for, that did have problems

 

[Cole@MBS]

the feed for the heater is stright off the battery pos! it one of the two leads, real pig of a job to get to, as its wired direct you cant disconnect it!!!!

 

[miko666]

I take it that this is not a five minute job then. The garage where I bought the car said this was not covered by the warranty but are prepared to pay for half of the cost, I think that is fair as I have only had the car a short time.

 

[Cole@MBS]

I take it that this is not a five minute job then. The garage where I bought the car said this was not covered by the warranty but are prepared to pay for half of the cost, I think that is fair as I have only had the car a short time.

give you some idea!

 

[miko666]

I see what you mean, it is quite involved. How much is the actual part for this?