Try replacing the disc battery in your remote/s.

 

Thanks, should I try my back up remote? Perhaps this will eliminate the remote as the problem?

 

Hello, I am frustrated with my red service battery light that comes on the dash every time I start the car. I can clear it with the button on my steering wheel. The car runs fine.

It all started when I replaced my consumer battery. I drained the battery over the winter sitting in my garage. I did have a issue with my trunk soft close, it was timing out the pump and popping the fuse because of a leak at the trunk latch. I think this was unrelated. I fixed the leak and reset the fuse and circuit so it is fine now.

I was told I set up the new battery incorrectly and went back and disconnected the starter battery and reconnected that battery first, then the consumer battery. In order I connected the starter battery then the consumer. The dreaded Light still comes on. Batteries are being charged by the alternator, ~14v when running. They batteries ran all summer with no issues. Light came on every time I started the car. I cleared and no issues with the car. Car is off road for winter and I want to fix now.

I did a parasitic test on all the fuses, they were all fine. I cant see any battery drain. I also have dug into the fuses behind the Bose subwoofer in the passenger floor, they are both fine. I was told it may be the 100 amp fuse. It was fine.

I am now frustrated that I cant find the problem. I am now wondering it the problem is with the N82/1? How about the K57 relay? Where is that? Can that be checked?

Does anyone have any further suggestions? Could it possibly be associated with the alternator voltage regulator. ? I think no because the batteries continue to charge when the engine is running.

Any help would be appreciated.

Try replacing the disc battery in your remote/s.

 

 

Battery control unit in the trunk may be at fault, it’s a very difficult problem to isolate without the wiring diagrams and functions description of the battery systems. I think your only hope is a good Tech with experience in the 230 systems. Call around Mercedes dealers and see if you can find one that has a senior Tech who worked on the older 230 models

 

different model, but had similar problem after battery replacement. I disconnected the trunk battery, then the starter battery and left them overnight. Reconnected starter battery, then trunk battery, reset display and problem was gone.
Now I'm worried about touching the SL batteries, but sooner or later...

 

I am now wondering it the problem is with the N82/1? How about the K57 relay?

You really ought to purchase a diagnostic tool which can read codes from the battery controller. A $120 Foxwell NT510 Elite is one option, an inexpensive Star Diagnosis clone costing $300-$450 is another.

 

If I down load this star software on my laptop, what will I need to connect to my car?

 

I am certainly no expert, but I would try disconnecting both batteries, and then disconnecting the 2 connections on the battery control module pictured in the trunk, wait a bit, and reconnect in reverse order.
I had the red battery warning appear after I added a battery tender to the rear battery and fully charged it.
I added a front battery tender and fully charged it, and the warning disappeared and hasn't come back. I'm guessing the battery control unit got confused when the rear was charged more then the front.
In any case, it might fix it, and you then you'll know where the unit is if you want to buy one and replace it.
Or you can just drive it as is since everything works.
Don't listen to me, I don't know anything.

 

View attachment 2676798
I am certainly no expert, but I would try disconnecting both batteries, and then disconnecting the 2 connections on the battery control module pictured in the trunk, wait a bit, and reconnect in reverse order.
I had the red battery warning appear after I added a battery tender to the rear battery and fully charged it.
I added a front battery tender and fully charged it, and the warning disappeared and hasn't come back. I'm guessing the battery control unit got confused when the rear was charged more then the front.
In any case, it might fix it, and you then you'll know where the unit is if you want to buy one and replace it.
Or you can just drive it as is since everything works.
Don't listen to me, I don't know anything.

Hello, Where in the trunk is this located? I cant seem to find it. I have a SL500 2006. There is a black box next to the positive terminal of the battery with a 25 amp fuse in it. However I cant see a silver unit like in your picture. Help!

 

When my red battery light was on, it was due to the 100Amp fuse being blown. That happened when the previous owner swapped batteries. I had to replace the main battery in the trunk (now it is the right type and capacity). The 100Amp fuse showed up on my scanner as a problem with the battery manager module (that charges the starter battery, that module is also called the Battery Stabilization Control module).
Anyway, that fuse is located behind the subwoofer in the passenger footwell.

 

I just reread your post, and it seems to say you connected the starter battery with the consumer battery not connected.
This is not correct. Your starter battery needs to be not connected when you connect or disconnect the consumer battery.
Somebody please correct me if I'm wrong.

 

cbr1000dude@aol.com

You are wrong.
It is the other way round.

 

cbr1000dude@aol.com

You are wrong.
It is the other way round.

I am wrong!

 

Hello, I am frustrated with my red service battery light that comes on the dash every time I start the car. I can clear it with the button on my steering wheel. The car runs fine.

It all started when I replaced my consumer battery. I drained the battery over the winter sitting in my garage. I did have a issue with my trunk soft close, it was timing out the pump and popping the fuse because of a leak at the trunk latch. I think this was unrelated. I fixed the leak and reset the fuse and circuit so it is fine now.
<big snip>

Any help would be appreciated.

Komish,

If you are still having problems with the Red Battery warning message, try disconnecting the rear-mounted consumer battery for a few hours; you can easily disconnect the negative terminal of the battery. After you re-connect the battery, (you will still likely have the Red Battery Warning message when you start the car) but then drive the car around for about 20-30 minutes, then stop the car and restart it a few minutes later. This exact sequence of actions "might" reset your electronic systems and the light will no longer appear on startup. This exact sequence of actions cured a persistent Red Warning message on my 2004 SL600 about a year ago and the warning message has not re-appeared.

BobTerry's advice to use a diagnostic tool to reset things is a more certain fix for the battery warning message, but the above sequence of actions worked for me. I think there is a fault code stored in the battery control module (BCM) if it ever detects a low voltage condition at startup; but the code can apparently be reset under certain conditions without a diagnostic tool; the above sequence worked for me, even though I had been experiencing a persistent Red Battery Warning message for several days after playing around a year ago and trying to determine how long the rear-mounted consumer battery would generate about 12.3 or 12.4 volts without being connected to a smart charger.

You should use a digital voltmeter periodically on your rear-mounted consumer battery to verify that your car's alternator and charging system is providing something over 13 volts to that battery when the engine is running at idle speeds and above when in Park. Please let us know when and how if you eventually eliminate the Red Warning message on your car.

 

Mine does this sometimes. I have a USB adapter that I can plug into my cigarette lighter that reads out voltage. What I see is that right after starting, my voltage is below12v for a brief period, then it kicks up to 14v. If I do anything that uses the consumer battery, such as sitting in the car listening to the radio with the engine off, it takes a little longer for voltage to rise after starting and I get a battery warning light. In my case, I think it's the crappy AdvanceAuto Chinese-rebuilt alternator I have. My alternator died and I was in a hurry and that was all I could get that day. I still have the original one that I keep meaning to get a new voltage regulator for, but I just haven't bothered.

 

Hello, I am frustrated with my red service battery light that comes on the dash every time I start the car. I can clear it with the button on my steering wheel. The car runs fine.

It all started when I replaced my consumer battery. I drained the battery over the winter sitting in my garage. I did have a issue with my trunk soft close, it was timing out the pump and popping the fuse because of a leak at the trunk latch. I think this was unrelated. I fixed the leak and reset the fuse and circuit so it is fine now.

I was told I set up the new battery incorrectly and went back and disconnected the starter battery and reconnected that battery first, then the consumer battery. In order I connected the starter battery then the consumer. The dreaded Light still comes on. Batteries are being charged by the alternator, ~14v when running. They batteries ran all summer with no issues. Light came on every time I started the car. I cleared and no issues with the car. Car is off road for winter and I want to fix now.

I did a parasitic test on all the fuses, they were all fine. I cant see any battery drain. I also have dug into the fuses behind the Bose subwoofer in the passenger floor, they are both fine. I was told it may be the 100 amp fuse. It was fine.

I am now frustrated that I cant find the problem. I am now wondering it the problem is with the N82/1? How about the K57 relay? Where is that? Can that be checked?

Does anyone have any further suggestions? Could it possibly be associated with the alternator voltage regulator. ? I think no because the batteries continue to charge when the engine is running.

Any help would be appreciated.

Hello, Just to close the situation here is the results to the fix. I purchased the Foxwell 510 Elite for the Benz. I scanned codes and there were two codes for the power supply control module. One was battery G1, one was 100A fuse. Both had been replaced and Red warning wouldn't go out. I cleared the codes with the foxwell, turned off the ignition after 10 seconds turned the system back on the red light stayed off! Started the car the light stayed off. Did this a few times , still was good. Re ran the codes and the foxwell had zero codes. All it needed all along was way to clear the code.

 

I was looking at the Foxwell. How do you like it? Is it's menu layout easy to go through?
I was going to get one off Amazon, but when I read one of the reviews about it not being pre-loaded and having to go to some Chinese website before you could use it, it made me leery.
The YouTube I looked at seemed like it was set up so it was really logical to use it's functions.
Torn between it and the ICarsoft MBII.

 

I picked up my car Feb. 17 and drove it 10 mins home and put it right in the garage. There it has sat ever since due to the weather and also it is a 3 1/2 week wait for MV appt. to get the title transferred and a set of plates for it. prior to me getting the car, it was sitting in a warehouse for about 9months.
I decided to pull the aftermarket radio out and in the process of some on and off ignition switch moves I got the big Red Battery warning, along with the Consumer Electronics are off line message and to Start vehicle. Thanks to finding old posts on this site it confirmed it was the trunk battery getting low.
I pulled the car out and let it run for about hour and all is well now.

The Foxwell NT510 Elite is due to be delivered tomorrow. Can't wait. I hope I can turn off "TeleAid" message in the dash.

 

so, can I just replace the consumer battery without touching the starter battery? Or do I follow this whole procedure to replace the consumer battery.
I have the red icon, occasionally, without the visit shop message. I load tested the start battery and it is STRONG, even under load. It was also replaced judging from its "new" appearance the the service history which only said, "replace battery."
The consumer battery looks pretty new also, but I didnt load test it, so Im just going to replace it. Should I just swap it out like I did this on my previous SL without issue?

 

I'd say it's just good practice to load test it before you spend the money, could be alternator, could need a code reset. However, your specific question re changing it, in the boot yes just swap it . It's AGM

 

yeah, thanks for confirmaion. I don't have a load tester, my friendly shop does and I'm not going back up there before the swap. Figure if the starter battery is strong and new, it's got to be the rear. If I'm wrong, I have a second battery that works for my buddy's trolling motor, and spring is here. He always needs a battery, so win/win
My understanding is the "visit shop" message comes up for no charging, alternator malfuction or low voltage in the charge circuit. I'll also drag out the XEntry system for codes and the like.

 

Only thing I can add is I had an aging starter battery for a long time. Even after a few days I would get the thing where the powers restricted "convienience functions unavailable" ( think the US message is something like "consumers offline" and the boot battery would charge up after a 10 or so mile drive. Eventually changed the starter battery (think a genuine MB is the way to go) and I cant remember the last time the boot battery threw a warning. Think it was carrying the starter battery. It's not that complicated a system but it can be difficult to pinpoint the issue.

Oh and another interesting point I have a digital battery tester - tested dozens of batteries, so I know its very accurate and it interestingly gives the 520ah starter battery a test rating 750ah. Which might be relevant when judging its state of health

 

Ive always trusted the old school testers that use a fat heating element and moves electrons. It’s a real test of the battery capacity. Are there things out there that are better?


Sent from my iPad using Tapatalk

 

Are there things out there that are better?

Foxwell BT100

 

I have a 2005 sl500 with 87k. Red battery light stays on. Trunk battery showing alternator charging and it reads 14 some, but starter battery shows 11 some. I checked power to alternator cable and it's there. Checked the 200 amp fuse behind the woofer and its goof. But the alternator connector with 2 wires has no ground or power weather car off or on. Any suggestions? I have to jump the trunk battery whenever the car dies for it to start, not the starter battery. Starter battery is benz gem and is new. But I don't drive the car. Whenever I leave the car for few days it's dead, trunk battery needs to be jumped. Charged it few times but I may have a parasite draining it, but still, not sure why its showing charging alternator and front isn't.

 

I would start with the batteries, as you have a new Mercedes starter battery thats good, buy a genuine Mercedes rear battery now, don't be tempted with an aftermarket, the Mercedes one is excellent. My worry is that as you have been jump starting the rear it damaged the BCM, as you MUST not jump start the rear if you refer to the manual, only the front. This asks the question as to why you were unable to jump start the front so I would be looking at the BCM next. Check for water ingress around it, check the heavy cable connections, then open the BCM and check there is no damage inside. I would strongly advise buying a diagnostic tool to learn more about what is going on, Launch, Kingbolen are all capable tools and there is a Black Friday sale on at the moment, here are some discount codes for you if it helps:

KINGBOLEN S800 Discount code BFCMS800 https://amzn.to/4fTFbRP X431 Pro Elite Discount code BFCM24FR Amazon.co.uk Kingbolen K7 Discount code BFCMDKK7 Amazon.co.uk

This video may help on the BCM access.

 

Thanks. I have an autel. I replaced the front battey cause it was done. I bought the car car which has been sitting at an old gu's house. Car would not start if i jumped the front as its strong and not dead, but when the back drains i have to jump it to start the car. But then i tickle chsrged it and the car would start fine and the liad test shows it to be good. But something is draining it wvery few days, which is another thing am gonna be working on. I also fixed the top hydraulic leak on it. Hvac head display doesnt come on at all. Radio comes on shows the main screen then shuts off if you touch any button. And the red battery light always on when i start it. So i left it aline and gave up. Then i digged more and found the alternator fuses under he passenger side woofer, geez. So checked the 200 amp and had power to both sides but the 100 amp behind it. It only has power to one side. Removed it and checked continuity and there is none. Ordered one hopefully that would solve sole of the issues. As when i start it sometimes the "some of the electronics are not working for unconvenient or whatever" comes on. All these years i had so many benz vehicles never knew that you are not supposed to jump this back one. But believe me car wouldnt start when the rear is low, something must be srianing it. It also wouldn't start cause the front was t charging even though its still showing 11 now after leaving the car running for a while

 

This makes a lot of sense as to why you cannot jump start from the front, if the resistor fuse has blown behind your sub, there is no continuity so fingers crossed buddy !
Your car should last for 3-4 weeks and start no issues even in the cold snow I work away and often leave my car for this period at the airport. Trust me the Mercedes batteries that are often branded by Varta are still made under Mercedes Quality Control and are very good. On the red cover at your rear battery it should say on it 'Do Not Jump' use front, have a look next time.
P.S worth checking that BCM too.

 

Its not an oem battery in rear. Didnt see it.