2004 sl350 with a catastrophic consumer drain

[zenteknika]

I have a 2004 sl350 with a catastrophic consumer drain on it - I was told it could well be linked to my alarm siren which no longer works and will require a new one as the battery acid will have knackered the old siren- shame they didn't design them to have a battery changed so it wont wreck the component- a new one is £105 and fitting another £120 so not cheap ! I think it needs coding to the car so cant do it at home mores the pity. If this is not the sole reason are there other reasons for a major drain ? I would be very interested to hear about Is there a designated sequence of tests you should do in order to narrow down the search and find the culprit? - I hear the electronics on these cars are a minefield to work through to fault find ! _ I already changed the battery for new but the problem persists-

 

[John Laidlaw]

I have a 2004 sl350 with a catastrophic consumer drain on it - I was told it could well be linked to my alarm siren which no longer works and will require a new one as the battery acid will have knackered the old siren- shame they didn't design them to have a battery changed so it wont wreck the component- a new one is £105 and fitting another £120 so not cheap ! I think it needs coding to the car so cant do it at home mores the pity. If this is not the sole reason are there other reasons for a major drain ? I would be very interested to hear about Is there a designated sequence of tests you should do in order to narrow down the search and find the culprit? - I hear the electronics on these cars are a minefield to work through to fault find ! _ I already changed the battery for new but the problem persists-

Unless a mod (@Blobcat ) spots this post, you’d be better starting a new thread in the electrical section, not many will spot it on here tagged to a 2013 thread .....

 

[Blobcat]

Unless a mod (@Blobcat ) spots this post, you’d be better starting a new thread in the electrical section, not many will spot it on here tagged to a 2013 thread .....

Thanks Johns, moved into a new thread

 

[grahamcol]

I think the alarm siren is actually plug & play, so you may be able to fit it yourself

 

[LostKiwi]

Which battery is going flat (there are 2).

 

[Blobcat]

Th

Which battery is going flat (there are 2).

Think it's the third one (alarm)

 

[LostKiwi]

Just reread your post and noted Consumer drain so rear one.
On ours the issue is Comand flattening the battery. Turn off Comand, let the battery go flat (which shuts down Comand completely) then as long as we don't turn Comand on again it doesn't go flat.

 

[AMGeed]

Don't pay £120 to have a new alarm siren fitted. It really is an easy DIY job and the new siren needs no programming.

N/S/F wheel off, remove arch liner closest to the bulkhead, undo the old siren with a security torx bit (T25 or T30 can't remember now), unplug old siren, remove old siren from bracket, refit new one in reverse order. Maximum of an hour for first timer.

 

[SL63 Mark]

If you connect a meter in series with the battery negative terminal and negative lead, and let the car go to sleep, you can pull the fuses one by one and check for what is causing the drain. That would be cheaper IMHO than replacing components. My car has a 50 mA drain at rest, which is normal for these cars. If I pull the left rear window fuse (fuse 62 IIRC) it goes down to 30mA, so something not quite right there.,

My car can be left for 2 weeks before the consumers message comes on, which is fine by me. Some people just connect a trickle charger and solve the problem that way.

It could be linked to the alarm siren, but it could be lots of other things.