Battery Drain W215 CL55 (2001)

[Needacupatea]

Hi!

Have seen a couple of threads on CLs draining their battery.. well now mine is doing it!

At first, I assumed it was the battery, so new Exide 100Ah battery fitted.. But no, still flattens the battery over a day or 2 of non use. In an effort to sort it, have removed the sat-nav CD and removed the CD changer cartridge as both had been flagged up by others as possible problems. Also taken out the phone! Having charged it last week, went to work and back (around 12 miles each way) Tuesday and Wednesday. Went out Thursday morning.. no go!! So battery gone flat overnight!!

Today I got home and set about trying to find the drain. Connected ammeter in line (used jump lead to 'bypass' meter while it sorted itself). On removing jump lead with car off, reading of around 500mA.. not enough to drain a battery but still far too much.. but leaving it for a while and watching, every couple of minutes, the current ramps up.. sometimes 2A, sometimes 3, sometimes over 5! then after around a minute, drops slowly back to 5-600mA.

Next step.. remove fuses. So I removed every fuse in the thing (2 boxes in bonnet, one under rear seat.. that's it isn't it??) None of the fuses made the reading drop.

So now I'm confused.. What circuits are there in the car that don't go through a fuse?? Or is there another fuse box I've missed? Any ideas what might cycle on/off like this?? HELP!!!!

Neil

 

[Dec]

Is the car alarm in working order?

Dec

 

[mersum1es]

You need to wait >> 6minutes that car goes to 'sleep', before actual measurement can be done.

Here are some (W211) related stuff:
http://www.mbclub.co.uk/forums/electronics/160239-battery-drain-driving-me-nuts.html

 

[Needacupatea]

Is the car alarm in working order?

Dec

Define working order!

Seriously though, it goes off when re-connect battery after it going flat.. Turns off with press of key button. It doesn't go off at other times when it shouldn't. Did go off when left her with windows down and someone reached inside.. not really sure what else I can check..

Would the alarm even draw 2+ amps?? Except if it was actually going off??

 

[Needacupatea]

You need to wait >> 6minutes that car goes to 'sleep', before actual measurement can be done.

Here are some (W211) related stuff:
http://www.mbclub.co.uk/forums/electronics/160239-battery-drain-driving-me-nuts.html

OK...I hadn't realised it wanted quite that long, but by the time I had finished going round pulling fuses must have been 20min.. and still doing same thing!

As for the link.. thanks.. interesting! Thing is mine seems to be pulling more than the 180mA for things not turning off and sometimes more than the figure for Bus being awake ?!

 

[Dec]

Working order is as in fit for purpose, it sounds and flashes hazards when triggered.
If your alarm is the original factory fitted alarm then its 12 years old and known to be troublesome at that age.

If it were cooking itself then it might be drawing 2+ amps, its worth testing it if it hasn’t been tested recently, just in case.

Dec

 

[Needacupatea]

Dec,

What sort of testing you thinking of?? It seems to all function as it should, but then I am not sure how it should!! I see mention of a backup battery.. should that cause it to go off when car battery disconnected?

Thanks for your help!

Neil

 

[Dec]

The idea of back up batteries is to trigger the alarm if someone cuts the wires, disconnecting the car battery and then reconnecting it may also be seen as an attack on the alarm, I think, when you reconnect a car battery the alarm should just rearm itself but it should not go off… but not quite sure about that.


To test, leave a window open or sit in the car and lock yourself inside, stay completely still for 60 seconds to let the alarm arm itself then open a door/s and or bonnet, the siren should go off and sound for about 15? seconds and the hazards should continue to flash for a further 90? Seconds after which time the alarm I think should then reset itself.

Unlocking and then opening the drivers door, if the alarm is armed, should also trigger the alarm.

Unlocking the car with the remote or turning on the ignition will disable the alarm.

While the alarm is armed a Red light should flash on the tow away switch.
On locking, hazards should flash 3 times.
On unlocking, hazards should flash 1 time.

It is something that is on all night and taken for granted so you have to check it is working ok.
Example of what can happen here… Alarm / Siren Issues : Goes off for no reason/Kills Battery FIX DIY.. - MBWorld.org Forums

Dec

 

[Needacupatea]

Thanks for that Dec!

I will have a play at the weekend. Now.. does anyone know where the alarm / sounder are in a W215???

 

[mercedescl500]

Thanks for that Dec!

I will have a play at the weekend. Now.. does anyone know where the alarm / sounder are in a W215???

In your earlier post you said you removed all the fuses from all the SAM modules but did you remove the Amplifier fuse ? The fuse to the amplifier is located on the amp itself inside the boot. The amplifier can be damaged by rain when it leaks into the cd/amp well because the drainage plug at the bottom gets clogged up. This can cause your amp to remain ON and not "sleep" which would cause a power drain. I would check this first before going any further. HTH

 

[Needacupatea]

In your earlier post you said you removed all the fuses from all the SAM modules but did you remove the Amplifier fuse ? The fuse to the amplifier is located on the amp itself inside the boot. The amplifier can be damaged by rain when it leaks into the cd/amp well because the drainage plug at the bottom gets clogged up. This can cause your amp to remain ON and not "sleep" which would cause a power drain. I would check this first before going any further. HTH

Thanks for that.. certainly worth a look... from your comments I assume its over near the CD changer?

Thanks everyone for the input... just hope can get it sorted soon!!

 

[mercedescl500]

Thanks for that.. certainly worth a look... from your comments I assume its over near the CD changer?

Thanks everyone for the input... just hope can get it sorted soon!!

Yes. The cd changer and amplifier come out together as one unit as they are both attached to the same bracket. If the changer or amp show signs of water damage this is likely to be your problem. The d2b fibre optic ring will not complete its loop to fall "asleep" as far as I know. Richard who is the resident COMAND expert on the forum might be worth contacting as he knows alot more about this than I do.

 

[Needacupatea]

OK.. thanks!

 

[ipohjohn]

There's some knowledgable people about who knows about electrical problems