In need of a Mercedes wizard

[GlenT93]

Im at my whits end here. I have a 2006 Mercedes e320 elegance .

My problems all started with a little boot leak which destroyed my battery control module (bcm) which caused my battery warning light to be constantly be in my face. however at the time I thought the problem was my brake battery under the bonnet so I replaced it first and found no faults had been sorted.

I then realised my mistake and changed the bcm but am still getting the battery light. I then found that some of the sleeve terminals had corroded and sheared so I used my aircraft fixing skills and re sleeved them and yeehah the lights went out.

Great success for about 3 days until driving along the motorway my car shit it’s self and gradualy started to die, gave me 30 error messages and caused my breaks to fail ( which was heavy scary btw) I assumed this time it was the alternator so have now replaced my
1. Alternator
2. Front brake battery
3. rear main battery
4. Battery control module

Now my car can sit all night long and hold a charge but once I go a drive it’s draining my battery until the car shuts down.

Even weirder is the fact I can put a multimeter on my battery and it shows 14v when the car is running.

So can someone please save me from this unknown gremlin that’s destroying my brain cells as I’m out of ideas

Thanks

 

[DSM10000]

Welcome to the Forum

The best advice is to stop throwing parts at it and have a local MB SPecialist with Star look at it to find any relevant fault codes etc.

We have a member on here (Woodythewise) who lives in Ayrshire, he may know someone. I can ask him if you wish?

 

[GlenT93]

Welcome to the Forum

The best advice is to stop throwing parts at it and have a local MB SPecialist with Star look at it to find any relevant fault codes etc.

We have a member on here (Woodythewise) who lives in Ayrshire, he may know someone. I can ask him if you wish?

Yeah that would be great I appreciate it! and tbh it’s an old car with few service history so I would have been replacing the batteries eventually anyway. The alternator just seemed to be the last link in the chain but apperently not.

I’m a mechanic myself and have also had a few garages try and work it out and there giving me nothing so it would be good to hear from someone with experience.

I’ve also had the sam module in the boot replaced a while back just incase he needs to know that but it’s probably be irrelevant

Thanks again

 

[WOODYTHEWISE]

Automotive Solutions | Home | Mercedes Servicing | Ayr
These guys are excellent. Both worked for MB Ayr prior to going independent.
Welcome to the forum.

 

[gbjeppm]

Based on what you describe, I would be checking the earthing points thoroughly, those symptoms sound familiar.

 

[GlenT93]

I’ll put a meter on them and see what the amp drain is, does anyone know what the correct drain Ampage should be ??

 

[GlenT93]

Automotive Solutions | Home | Mercedes Servicing | Ayr
These guys are excellent. Both worked for MB Ayr prior to going independent.
Welcome to the forum.

Thanks for that I’ve actualy heard about these guys before but have never been able to find them all I knew was they were in the whitlets area but that’s great I’ll give them a buzz tomorow, good man

 

[DSM10000]

Thanks for that I’ve actualy heard about these guys before but have never been able to find them all I knew was they were in the whitlets area but that’s great I’ll give them a buzz tomorow, good man

John (Woodythewise) has high standards and will not just let anyone work on his cars, if he recommends them then that would be good enough for me.

Hope you get it sorted!

 

[gbjeppm]

I’ll put a meter on them and see what the amp drain is, does anyone know what the correct drain Ampage should be ??

It should be under 50 milliamps.

You may need to wait for up to 30 minutes for the car to fully shut down.

 

[GlenT93]

It should be under 50 milliamps.

You may need to wait for up to 30 minutes for the car to fully shut down.

Spot on cheers mate

 

[merc85]

Have checked the condition of the loom where it enters the boot? this can split and wear with the action of opening and closing the boot.

 

[Deletedmember130310]

What does the brake battery do? I’ve nver heard of one.

 

[merc85]

In the event that the large battery in the boot dies, the small aux battery takes over and still provides power to the SBC brakes.

 

[GlenT93]

A little update for everyone!!

I went to the Mercedes guys at whitlets and long story short I was right enough to fit a new alternator , but unfortunately the new one I bought was faulty.
So I’ve had it changed for another one (after 4 hours looking for my invoice) fitted it and yehah she is back to life. The beast is back!

Thanks for the help everyone