Urgh so is it my alternator now or BCM?
#1
MBWorld Fanatic!
Thread Starter
Urgh so is it my alternator now or BCM?
My electrical saga continues.
My car has been behaving well of late and the charging system was showning a healthy 14.2 whenever the engine was running - then out of the blue, I start my car on Saturday (5 days ago now) and I get the red battery message. After driving it some time thinking it was my aux battery module (for the third time!) the car eventually flipped out and started beeping at me with brake warnings and gave me battery/alternator warnings. When I got home, i measured the current at the battery with the engine on and it was 10.88...oh dear, it wasn't charging at all.
So I decide to clutch at straws and blame it on the poor ebay voltage regulator being bad after just three weeks in the job (I wasn't having charging problems before, but I was getting the convenience message a lot, so thought I'd change it as part of good practice) - today I installed my shiny MB supplied Bosch regulator and....nope, problem still exists
Disappointed at the result of the new regulator, I quickly went back under the car with the engine running and tried to measure direct from there to see if the problem lay with the BCM. Now excuse my ignorance here, I've never done this before so not sure if I've done this correctly - I kept my volt meter in the same mode I use for checking my battery voltage and then I placed the red pin on the shiny metal nut in the middle of the alternator with the power cable and then the black pin on the clean metal part of the block....was this right? I managed to get a reading, albeit an unstable one but I could generally make out something consistent showing ~10.8v...although if I've not done it right, that might not mean anything.
Advice on how I can tackle this would be appreciated, please.
My car has been behaving well of late and the charging system was showning a healthy 14.2 whenever the engine was running - then out of the blue, I start my car on Saturday (5 days ago now) and I get the red battery message. After driving it some time thinking it was my aux battery module (for the third time!) the car eventually flipped out and started beeping at me with brake warnings and gave me battery/alternator warnings. When I got home, i measured the current at the battery with the engine on and it was 10.88...oh dear, it wasn't charging at all.
So I decide to clutch at straws and blame it on the poor ebay voltage regulator being bad after just three weeks in the job (I wasn't having charging problems before, but I was getting the convenience message a lot, so thought I'd change it as part of good practice) - today I installed my shiny MB supplied Bosch regulator and....nope, problem still exists
Disappointed at the result of the new regulator, I quickly went back under the car with the engine running and tried to measure direct from there to see if the problem lay with the BCM. Now excuse my ignorance here, I've never done this before so not sure if I've done this correctly - I kept my volt meter in the same mode I use for checking my battery voltage and then I placed the red pin on the shiny metal nut in the middle of the alternator with the power cable and then the black pin on the clean metal part of the block....was this right? I managed to get a reading, albeit an unstable one but I could generally make out something consistent showing ~10.8v...although if I've not done it right, that might not mean anything.
Advice on how I can tackle this would be appreciated, please.
#3
MBWorld Fanatic!
Take it to one of the auto places and they will use the Mintex charging machine to test your charging system and give you a readout. If you do need an alternator. It's part Bosch al0826n. I bought one but ended up not needing it. Was my bcm and front aux relay
#4
MBWorld Fanatic!
Thread Starter
Ok so nope, battery still not being charged after having changed the BCM. Old one was fine anyway, but I wanted to be **** as the whole thing seems to be having problems so I changed it as preventative maintenance.
Ahem....well, it's freezing over here in the uk now, so I'm gonna wait for the temps to rise a bit again....maybe middle of next week and then I'll get to work on getting the alternator out. I'm really not looking forward to it... It's so cold
Ahem....well, it's freezing over here in the uk now, so I'm gonna wait for the temps to rise a bit again....maybe middle of next week and then I'll get to work on getting the alternator out. I'm really not looking forward to it... It's so cold
#5
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W211 E270cdi airmatic 4matic 211.016
Ok so nope, battery still not being charged after having changed the BCM. Old one was fine anyway, but I wanted to be **** as the whole thing seems to be having problems so I changed it as preventative maintenance.
Ahem....well, it's freezing over here in the uk now, so I'm gonna wait for the temps to rise a bit again....maybe middle of next week and then I'll get to work on getting the alternator out. I'm really not looking forward to it... It's so cold
Ahem....well, it's freezing over here in the uk now, so I'm gonna wait for the temps to rise a bit again....maybe middle of next week and then I'll get to work on getting the alternator out. I'm really not looking forward to it... It's so cold
Do you find what was the trouble? Do you Fix it? I have the same, and at night when all it's working it seams that reset system, rádio and parktronic turn off then on for a secund, wird.
Thanks