Nomondays ForMe

Had to use the physical key to unlock the car door.
No dash lights, no dome light, no headlamp or tail lights, no horn, no accessories, nothing that's battery powered will function.
The battery under the hood is Functional, terminals are not corroded, and it's FULLY charged.
Unable to unlock the trunk electrically and the manual key won't unlock it either.
Is there a "Master" Fuse or Circuit Breaker that can cause this symptom?
If so, please describe where it's located.
If not can somebody please tell me what to check, where to look for the cause.

Utopia Texas

This is the R231 forum. I believe your SL is a R230. You will get better answers there......

Nomondays ForMe

Okay, thank you. Will do!
BTW - I had the SL550 Flat-bedded to the Mercedes Dealer for them to troubleshoot and repair the problem.
When the problem is found and remedied I'll post the result(s) on the R230 Forum.

dsmall7777

Dead Car

2008 R230 SL550 86k miles
.
No electrical power. I had to use the physical key to unlock the car door. The FOB won't turn in the ignition to start the car.
Nothing works.. 2 New batteries (fully charged). Clean battery contact poles
No dash lights, no dome light, no headlamp or tail lights, no horn, no accessories, nothing that's battery powered will function.


Any advice?

David

bob55

The Battery Control Module has likely shorted out. This is a known issue on 230's and has caused many trunk fires in the past. The BCM is located in the right rear section of the 230 trunk but behind the covered area. You must take apart the trunk lining to get to it. If you notice a sulfer type of smell, (electrical burning smell), when you open the 230's trunk that's a clue the BCM has failed. .

If indeed the BCM on your 230 is the problem, just consider yourself lucky the car didn't burn. And should that happen inside your garage, your home could b burned down as well. .

Do a search in the 230 forum for 'trunk fire'. It's a lot more common that you might think!

dsmall7777

Thanks for the quick reply.

I saw a thread from a SL550 owner stating his car was on fire in Hawaii and almost burned down his house. Fire department responded to put out the fire and dragged the car out of the garage.

If that is the problem, why won't the key fob turn in the ignition? Is that also controlled by the convenience trunk battery which is short circuited?

I checked out BCM's online and was quoted $750/$800 new. Used $400. Should I try a used one?

Thank You.

David

Utopia Texas

Your car, your choice. I personally would not put a used electrical part in my SL that is already suspect for problems.

bob55

if the BCM short circuits, it's unlikely there will be any power available to any area of the car from either battery, but there will likely be some "electrical sparking' going on inside the BCM itself as long as the battery is good which is why there is such a danger for an electrical fire inside the trunk.

If you suspect a BCM failure, (i.e. it has shorted out), then you should immediately disconnect both the 230's batteries to prevent a possible fire. This is a very serious electrical system issue and best handled by MB Dealer Service. I don't recommend attempting a 'do it yourself fix' for any kind of BCM issue. The BCM is a complex electronics module that affects virtually all areas of the car that use electrical power..

The' horror story' video you mentioned on the 230 forum is just one of many instances of this occurring. It is far more common that you might realize. In fact, it happened to me inside my garage. The garage was filled with smoke and flames 6-feet high were apparent at the rear of my SL500 when I discovered the fire. The aluminum skin had completely melted away just beneath the gas filler cap and a rear tire was now on fire when I opened the door leading to my garage. Due to proximity to the fuel area, I was very concerned the gas tank might explode. (BTW, the car had not even been driven for several days when this fire occurred).

Had I not checked my garage just before going to bed that night, my house may have burned down along with my (3) MB's. My wife and I may even have even died because we were about to go to sleep for the night..

Luckily, I was able to douse the flames with a garden hose, thereby avoiding the worse scenario. However, the car was completely dead and could not be moved from the garage, Smoke was still coming out of the backseat area and the trunk which would not open. When the Fire Department arrived we finally got the trunk lid open and found the BCM itself was still 'sparking and burning' along with some of the trunk lining. . Disconnecting both the batteries was the only way to stop it.

Soon afterwards, my 230 was declared a total loss by an Insurance Adjuster due to fire, smoke and water damage, but thankfully there wasn't very much damage done inside of my garage, other than a partially burned golf bag. I used the insurance settlement as a down payment on my present 231.

I consider the BCM in the 230 series a very serious fire hazard that affects all model years from 2003 thru 2012. IMO, there really should have been an MB recall for all those SL models to check the BCM for electrical shorting problems. Anyone who owns a 230 should have the BCM inspected as soon as possible due to the risk of a potential fire. I think many of those inspections would reveal evidence of 'overheating' and 'evidence of electrical burning inside the troublesome Battery Control Module.

Good Luck in getting your 230 fixed! As previously mentioned, this thread really belongs in the 230 forum rather than the 231 forum.

dsmall7777

Good advice. Thanks for the reply.

I have a MB mechanic who suggested the same thing to replace the ESC module. Confirmed now.

Also, I noticed there are several firms online that will rebuild your module under $300. This seems like a cost effective alternative vs $1,200 new or refurbished for $800. Plus consider a dealer's charges of installation and markup, $2k+..

David

dsmall7777

dsmall7777

R230 2008

This was the problem. BSCM was fried. This could have set the car on fire as previous posts witnessed.

bob55

Consider yourself extremely lucky not to have experienced such a fire. The 230's BCM is clearly flawed, and problems with it are way more common than 230 Owners know. Frankly, I'm surprised there haven't been more lawsuits over MB's failure to issue a recall for an inspection and possible replacement of 230 BCM's. (I do know there have been several lawsuits filed as a result of BCM fires, but so far, nothing like a Class Action Suit; has been filed that would force MB to do something about this).

I expect more 230 trunk fires will occur due to these faulty Battery Control Modules. The resulting fires will continue to cause significant property damage, but I pray there will be no loss of life.

When a 230 is parked inside a home garage the risk for very significant damage is much greater. .



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