Mercedes SL R230 Battery Control Module BCM Fault

This faulty BCM was resulting in the rear consumer battery to go flat after a couple of days, however no warning lights were appearing on the dash. On inspection there was a bad burning smell and I open the module to have a view inside

[MikesMercsandothercars]

Another great video detailing a common problem with the R230. I have done a few battery drain videos but thankfully not had this issue...yet. Mike

[JoelBlauvelt]

Which screws need to be removed to extract the board from the box? All of them?

[GNXClone]

These are going for well over $1000 USD now on eBay, used!

[endaf]

Mine was slightly worse than yours, i could smell that it was getting hot, so took it out asap.

Btw that smell stays around for days....

[AaronsTalks]

Thanks for the video. My starter battery has not been charging off the alternator for the last month. I replaced the 100A fuse, didn't work. Today, I put my boot in to service mode (to change a taillight bulb), then turned the car off and this started burning... I panicked and pulled the carpet up. Luckily the burning didn't spread outside the module. I have a question... Is there a way to bypass the K57 relay and remove the starter battery so that there is only 1 battery in the car, running everything?

[troysimon]

Can you measure the size of the nine blue 470uf capacitors - 13mm x 25mm? I want to order them before I remove the BCM, these old caps can cause you SL to go up flames!

[MikesMercsandothercars]

Hi Dave - hope you are well. Do you still have this faulty BCM or any other faulty BCM's? I am thinking of doing a 'How BCM's work, what goes wrong with them and why they can catch fire video. Ideally, I need a sample faulty one. Let me know - hopefully you still have my mobile. Mike in Bristol

[Richard]

Is water the only reason for the damage?