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Red battery light on display...anyone ever have this issue? battery? or alternator?

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S-Class (W221) 2007-2013: S 320 CDI, S 350, S 450, S 500, S 550, S 420 CDI, S 600

Red battery light on display...anyone ever have this issue? battery? or alternator?

 
Old 09-01-2013, 12:38 AM
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Red battery light on display...anyone ever have this issue? battery? or alternator?

red battery light indicator comes on in the instrument display signalling an issue with the charging system of the car i guess.
when i turn the car off and back on,it disappears for a while...sometimes and hour, sometimes 2 hours or more. but lately been doing it within an hour to two of shutting and restarting the car. In all cases, car drives absolutely fine and normal.no loss of power anywhere whatsoever.
Anyone experience this? Am guessing its either the alternator or one of the batteries. Just want to see if anyone has had a similar issue.


Thanks
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Old 09-01-2013, 01:04 PM
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2008 S550 4Matic
Just the small starter battery. Just replaced mine wit a similar issue
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Old 09-20-2013, 09:07 PM
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Just an update in case anyone faces a similar issue,it was the alternator that was faulty. Alternator changed and everything back to smooth running.

Last edited by just1time; 09-20-2013 at 09:26 PM.
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Old 09-20-2013, 09:23 PM
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2010 E350 4Matic
How much?
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Old 09-20-2013, 09:46 PM
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hey

Originally Posted by MBNUT1 View Post
How much?
everything cost $600. But this was done through my personal mechanic and covered by my extended third party warranty.
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Old 04-05-2017, 07:10 PM
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Mercedes S550 2007
Meaning of Red Battery Warning Light in MB's

I recently had an intermittent red battery warning light popping up in my instrument cluster of my 2007 MB S550 (W221). I feared that it could be Alternator or the Control Module. This battery warning light icon comes in two colors Orange and Red. Orange means that battery is temporarily low on voltage and Red icon means that battery is not charging.


I took my S550 to a MB dealership to test and confirm the cause. They tested the front auxilary starter battery (smaller battery in the passenger side front hood) and it tested fine while running and under load. They then tested the trunk battery (big main 180Amp battery) and it showed 14V while the vehicle was running and very low voltage under load and when engine not running. The big battery in the trunk was the culprit.


In short if you see only the red battery icon with no verbiage then it's one of the failing batteries needing replacement. If your vehicle has problem with the Alternator, Voltage Regulator or the Control Module then the red battery icon will accompany text "Visit the Workshop".


This was what I found from my experience. The front small battery sells for $89 and the large trunk battery for $190 at the Autozone and works equally well with three years warranty.
Attached Thumbnails Red battery light on display...anyone ever have this issue? battery? or alternator?-mb__red_warning_light.jpg  
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Old 04-06-2017, 12:03 AM
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Is this the first time you've replaced the battery in the trunk?
Mine is 08 with 31000 miles and I had to replace the starter battery last year.
Consumer battery in the trunk is still good, but I'm wondering how long it's supposed to last, it's been ten years. Then again, I had Porsche Cayenne and its original battery lasted 9 years and 110,000 miles before replacement.
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Old 04-06-2017, 12:20 AM
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Actually the consumer battery in the trunk does most of the heavy lifting and is critical. I replaced this battery for the first time in 9 years and this was the original Bosch Varta battery. If your vehicle is 8-9 years old and you have not changed then it is pretty much approaching the end of its life cycle. This battery at this stage will sneak up on you intermittently and then very quickly die out at this age. A lot of mechanics will try to take advantage of your urgency by tricking you in to buying an $850 rebuilt Alternator but that is totally unnecessary.

This is a pretty cool DIY project and for your 2008 MBZ although you have low mileage, but I will recommend you to replace this consumer battery so it does not die on you when you need it most. MB dealership sells the original Bosch Varta for $240+tax with a core refund of $18. Be aware that this battery weighs 75lbs. My advise buy Duralast from Autozone for $190 with $18 core refund and then install it yourself as a mechanic will not do this as nicely and carefully as you will. To DIY it, you will need to pry out the cardboard firewall in your trunk behind the rear seat from within the trunk. This battery is located on the right passenger side under circuit boards and lots of connections. All you need to do is to open one (1) screw in the bottom and the belt harness will come out, carefully disconnect -ve terminal first and then the +ve one. Gently move the battery left and right several times to slide it out from a cramped slot and put the replacement battery in. You will have to sit inside the trunk to do this job. Total time from start to end to do this battery replacement is approximately 30 minutes.

Also don't forget to put anti-corrosive gel and red/black round pads around the two electrodes of the new battery. Seat round pads first and then apply small quantity of gel around and on top of both the electrodes. As a word of caution after the new consumer battery is installed and it kicks in a lot of stuff in your car like windows and several instruments will not function normally for at least an hour. You will hear a lot of faint click and clock sounds from all around your car. The reason is the main vehicle control computer located in the left side wall of the trunk will reboot and will perform self test, diagnostics and auto-calibration procedures. Once the computer is fully rebooted, it will re-calibrate every sensor and actuator in the car and that will take some time. No need to be alarmed. Try to manually power up and down the windows and they will start functioning normally within few minutes. Preferably after one hour after installing new battery, drive your car for about 30 miles to fully charge the new battery and for the rebooted computer to generate and build vehicle related data. Love this self-calibrating German engineering!

Last edited by amriyaz; 04-06-2017 at 01:15 AM.
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Old 04-06-2017, 10:12 AM
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amriyaz, thank you for your comments.
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Old 10-02-2017, 11:57 PM
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2011 S550
Battery sign

my 2011 s 550 battery sign came up I replaced the main battery the sign didn't go away , I replace the altinator the sign still shows what do I do next anyone with the same issue please help
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Old 10-03-2017, 12:14 AM
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Mercedes S550 2007
Battery Sign

Originally Posted by Lucy Begian View Post
my 2011 s 550 battery sign came up I replaced the main battery the sign didn't go away , I replace the altinator the sign still shows what do I do next anyone with the same issue please help

First thing you should do is to change the other battery. S550 has two batteries one under the hood and the other in the trunk. Hopefully this should fix this. If you still get a red battery sign then it means that the control module that manages both the batteries needs replacement. That is an expensive part to replace so hopefully second battery change may do the job.
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Old 10-03-2017, 12:24 AM
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Mercedes S550 2007
Btw be very careful about the red battery sign on your dashboard as it means that the batteries in your car are not being charged and pretty soon they will be discharged and may get permanently damaged. The S550 is an advanced vehicle and almost all its critical systems are electrically driven. The transmission on this vehicle is also electrical and low voltage and current can also potentially damage it. My recommendation is to treat this matter as urgent before this situation causes unnecessary damage to your vehicle.
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Old 10-03-2017, 10:23 AM
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I believe that 2011 has just one battery under the hood, and no battery in the trunk.
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Old 10-20-2017, 08:16 PM
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2011 W221 S550 4MATIC, 2000 W202 C180 WAGON, 1998 W210 E240
"I believe that 2011 has just one battery under the hood, and no battery in the trunk."

You are correct.

Last edited by MercMuscle; 10-20-2017 at 08:17 PM. Reason: add quote
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Old 04-07-2019, 07:51 AM
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Mercedes E320 bluetec
Battery light

2008 E320 diesel, I changed battery and alternator still intermittent battery light, no message though
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Old 04-07-2019, 08:26 AM
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2011 W221 S550 4MATIC, 2000 W202 C180 WAGON, 1998 W210 E240
Originally Posted by Maconbob View Post
2008 E320 diesel, I changed battery and alternator still intermittent battery light, no message though
My issue turned out to be a bad ECM not sending a signal to the voltage regulator on the back of the alternator. That in turn led to the battery not being charged.
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Old 04-07-2019, 08:54 AM
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Battery light

Thanks Mercmuscle, but my battery seems to be charging
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