When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
djbadeaux: Anytime I can help someone avoid the MB dealer service ripoff, I am ecstatic! For an electrical problem like this, all it takes is for someone to invest the time to understand the schematics and share the knowledge.
Buddy, I owe you cocktail and then some! I finally set aside the time to tackle my red battery light issue. You were not lying when you mentioned how hard it was to get to the 100 amp fuse. But after several hours, bloody knuckles, and some sore *** ribs from laying on my side into the car, I removed a blown fuse! To my delight and $6 later, I inserted the new fuse, cranked her up, and voila... NO RED BATTERY LIGHT!
To think that the Mercedes dealership wanted to change my front passenger SAM for $1000 in order to fix my battery light problem infuriates me. Those ****ers couldn't even guarantee that changing the SAM would fix my problem! And in my case it would NOT have.
Thanks again CPDAY! And thank you MBWorld!!!!
yeah, those fuses..! there must be some compelling reason MBz would put a flocking fuse in an inaccessible place but i'm sure that could have been re-engineered..
if my dealer had tole me $1000 for the part + labor i would have demanded a refund if it did NOT work..
which is, i suppose, part of the reason out-of-warranty MBz cars have crappy resale value..
i just don't understand MBz's thinking on this sort ofd thing.. it all goes to reputation..
I have the dreaded red battery light on for my 2007 SL550 I have replaced the rear battery and front batteries within the past month. Both batteries are charging properly.
The rear battery drains if the car is not driven for a few days, from my understanding that is a regular issue with the dual battery system.
I have checked all fuses and relays, including the ones under the passenger floor behind the subwoofer. And they are all working.
Also the radio/nav/command centre does not work. Turns on for 15 to 20 seconds then shuts off. I am check the SAM and the audio gateway as we speak.
I can't help but believe they are all interconnected.
Any answers help or suggestions would be greatly appreciated.
Welcome to the forum! Please take a moment to visit the User Control Panel and update your profile to include your location (at least country). This information will then appear below your name and avatar on the left side panel next to each post you make. This will greatly help others to give you better information. If you are using the mobile version of the site, you will need to switch to the "full" version to get to the User Control Panel.
Not driving the car for a few days shouldn't discharge the battery. A few weeks, maybe, not just days. I think you have something draining the battery. One thing it could be is a leak in the PSE system that causes the pump to run continuously. The trunk latch is a common cause of that. Another item that can be a voltage drain is the fan in the overhead control panel that runs after the ignition is switched off. You need to find and fix the voltage drain. In the meantime, you can use a C-Tek charger to keep the battery maintained, but that is not a long term solution.
Regarding the radio, when the ignition is switched on, it sends a signal over the CAN bus to activate it. If there is a problem with the CAN bus connection to the radio, it won't get that signal, so when you press the power button to turn it on, it acts like the ignition is off. In that case, the radio will power up, but only operates for about 10 minutes. But you said 15-20 seconds, so that doesn't seem to be the same issue. I think the only relation between you battery issue and the radio would just be related to low voltage. Fix the battery drain issue first, and if that doesn't fix the radio, then look at its wiring.
Beautiful! Spent a good half a day following the steps on the first page of this thread only to find out both fuses were fine. Tested w/ my multimeter. What would you think the best to tackle next?
Why do I have the red battery message? The consumer battery was almost dead. Removed it out of the car to put it under trickle charger. When installing back in, I managed to short positive post to the chassis. An immediate spark and I pulled the ratchet quick. Next time I started the car, the red message was on my instrument cluster. I'm not saying the incident caused the red message. I'm just saying this is what happened.
Other tests I did prior,
- starter battery is fine
- consumer battery is brand new
- alternator is fine
- no faulty codes
Just one comment: To test the two fuses (F52f1 & F52f2), one needs to remove them or at least disconnect one side of each fuse. I hope that you did this. As discussed earlier, testing them in place may fool you, as voltage may be found on both sides of a blown fuse in this circuit. Yes, it is complicated, but believe me, it is true.
I know that after digging all the way down to the fuses, it is one more pain in the neck to actually remove them. The fuses are so cheap and readily available, that I usually advise people to just replace them and see what happens.
Thanks CPDay! I removed both of them and boy what a thrill that was. You can't imagine how accomplished I felt as I was holding them in my hand I'm with you on your last comment. If you get to the fuses, replace them anyway. I didn't have the replacement parts and it was getting dark and I had to wrap it up quick.
Rodeo- As you are now waiting for the new F52 fuses to arrive, could you do a simple continuity test across each of the two removed fuses? If either of them are blown, that’s important information.
Regarding the other (F32) fuses: You could always test them, but... what, exactly, was happening with the consumer battery before the Red Battery warning started? Perhaps we can figure this out before you spend money on SAM’s, etc.
Thanks CPDay! Allow me to clarify. By wrapping up I meant I put everything back together. In fact, I can't stop driving my car and I'm not waiting for the parts to arrive.
I ran all kinds of continuity, resistance, voltage tests and anything I could imagine on the fuses. I could also tell from the look of the fuses. The visual test passed as well. Re. the consumer battery, it was dead or half dead I think. Also it was a lead acid battery so it had to be replaced but I think I waited too long. For maybe 5 or 6 months I had the infamous consumer battery offline message on my cluster which I ignored. The car wasn't being driven long trips so the message was expected. Everything was fine till I shorted the positive post of the consumer battery to the chassis when the battery was attached to the car, which made a spark. Then I got the red battery message next time I started the car. I searched here on the forum and people were saying replace the battery and the red message goes away but mine didn't.
Rodeo- Ah, so someone installed a plain-vanilla lead acid battery in your trunk? By itself, I’m not sure that would be a serious problem, but AGM’s do have different charging profiles. There are AGM batteries that can replace the factory trunk battery and are much less expensive than the MB version. I would certainly want to get a new (and charged) AGM battery into the trunk before I tried anything else. If you do this, be careful around the bare terminals when installing. CPDay
I think I already went over this. The battery in the trunk was replaced with a brand new Odyssey group 48. The nominal CCA of the battery is 723 A but after talking with Odyssey they made it clear the battery would/could/should produce 1050A in the first 5 seconds which is way more than what R230 is calling for. Just for the records, no sparks this time I installed the battery This replacement was weeks ago. The red battery message still persists though.
Tried using the procedure and photos from an earlier post to pull the subwoofer to check the fuses. Got it out after 30 minutes of pull here, pull there. Fuses were good...Trying to put it back together has been several failed attempts to get it back on the posts correctly. The bottom is too far forward (towards the seat) and won't push back far enough to get it on the post. Unfortunately my carpet doesn't pull back near as far as the one in the earlier photos so I have limited room and visibility.. I have a 2005 SL500. Was wondering if it would make it easier to peel back the carpet from the sides in order to peel the carpet back furtehr. Does any know know how to pull out the passenger well kick carpet (right side) out? Plus how to peel back the carpet from the left side? Any suggestions would be greatly appreciated... already wrenched my back getting this far... ugh...
Don't bother peeling back the carpet any further where you rest your feet. Focus on the subwoofer housing itself. First make sure you're not babying the subwoofer. Be a little more aggressive to the point that you know you're not making any damage.
That right side carpeting comes off easily. I think it helps a bit if you get it out of the way. That gives you more room to play with. Take the screw cap off with a plastic pry tool then undo the screw, then pull. I remember I pried the trim molding off, the one that says SL or AMG on it depending on your model, before the side carpeting just to make sure I'm not breaking anything. Pull it up and it comes right off.
The left side carpeting makes no difference in the process so don't even bother.
Here's how you fit the subwoofer housing in its place, bottom left first, top left second, bottom right third, top right last. The left side goes in easily, the right side might need a little push. You need to make sure you align the bolts attached to the chassis and the holes in the subwoofer housing throughout the whole process.
Thanks for the advice!!! It's exactly what was needed! Got everything put back in. Unfortunately the dreaded battery icon / Visit Workshop alarm is still coming up. This all started after I replaced the consumer battery. It was continuously losing charge, causing all kinds of issues. I replaced it with the OEM battery; that's when the battery icon started appearing. Innova scanner says there is no reset required and it does clear itself after restarting, but then quickly reappears. When I replaced the consumer battery, I didn't disconnect the starter battery, not sure if that has messed something up or not. Still searching for answers.... Also have a P0123 / P120 alarm, which is the accelerator sensor. I have a new accelerator pedal on order which should resolve that (hopefully)... Just need to figure out the batter icon alarm...
I have been saying this for years in this thread, but I’m not sure that I have been real clear regarding the two fuses in question: To be tested, they need to be electrically isolated from the battery management circuits. This is because both voltage and continuity tests on the connected fuses can be misleading. The fuses reside within circuits that can show back-continuity on a multimeter and 12v can be found on either terminal in these circuits. These are LARGE capacity fuses that get blown by electrical spikes, like jump starts or shorts.
After making all the effort to get to the fuses, it is best to then remove them and check them on the bench with a multimeter, OR just flat-out replace them with new ones. They are inexpensive.
CPDay- What if I disconnect both batteries and wait a little to let any existing current out of the electrical system. Do you think that works or there are other here and there small batteries connected to other components as well that might put small current on the fuses?
The "Dual Battery" document which was posted a few posts back explains that there are cases where a code set in the battery control module will trigger the red battery indicator in the cluster, and this condition will remain until the code is erased.
Looking at the schematic in that same document, it is apparent that all fuses can be checked without the need for accessing them in the passenger footwell. For example, if voltage measurements reveal that both front and rear batteries are being charged with the engine idling, then the two fuses in block F52 are good.
Thanks bobterry99 for the input. That's actually why I've been in fingers crossed position for quite some time now. Plan is to remove the error message and see if it comes back. Most posts in this thread suggest that it comes back cause if everything was fine the red message would go away automatically. I'm just hoping I prove it wrong. Just for the records, the cost of removing the error is $97.40 at my sweet dealer.
I think that we need to be clear on what "checked" means with regard to the fuses. I originally diagnosed (and fixed) my red battery warning by continuously monitoring the voltage at each battery to be sure that they were reeceiving charging voltages. As it turned out, my front battery was not receiving the 14-or-so volts needed for charging, BUT it took days of monitoring to be sure that this was the case. It would have been a lot quicker and easier for me to have removed the fuses and bench-tested them.
Just for the records, the cost of removing the error is $97.40 at my sweet dealer.
For a bit more than that you could buy an iCarsoft 980 to read and erase the code. Or better still spend $325 on a Chinese Star Diagnosis kit.
Originally Posted by CPDay
As it turned out, my front battery was not receiving the 14-or-so volts needed for charging, BUT it took days of monitoring to be sure that this was the case.
I don't understand why it took days. At any rate, a simpler method is to disconnect the ground cable to the rear battery, insert the key into the ignition switch, and attempt to turn the key: If it turns, fuse F52f1 is presumed good.
The battery management circuit switches the 14+V charging on, off and between batteries to “optimize” the batteries. I watched this through several days of driving before concluding what was actually happening. Perhaps this was a slow process, but I did fix the red battery warning with a $10 voltmeter and a $6 fuse.
Very true and I'm glad you fixed it so smart but don't factor out the chance parameter. It seems in some cases the culprit could be the N82/1 control module in the trunk, which is not necessarily a cheap fix. Not to scare the thing out of anyone but to have an idea that digging all the way down to the fuses is not the easiest fix in the world but it could end up being the cheapest fix.
It may be helpful to go back to the start of this thread (from 3-1/2 years ago!). I went through the “is it the fuse or the N82/1 unit” decision, and decided to dig down to the fuse FIRST, because the N82/1 was way more $$. You can see on this forum that R230 owners are often advised by dealer techs and other experts to replace batteries, SAM’s, N82/1’s, and other big-ticket items when they get a red battery warning. That advice may be good in some cases, but I tend toward trying the cheap and simple solutions first.
I recently fixed my failed ABC system that had catastrophically blown out it’s hydraulic fluid on the highway. I expected it would cost me thousands, but in the end I fixed it myself by replacing an O-ring. Yes, an O-ring.
where does it go?
Well, apparently I was in too much of a hurry to put everything back together when replacing the consumer battery ...... it appears I left something out, found this next to the old battery yesterday... but don't remember where it goes?
02-15-2016, 10:24 AM
I'm with you on your last comment. If you get to the fuses, replace them anyway. I didn't have the replacement parts and it was getting dark and I had to wrap it up quick.
This replacement was weeks ago. The red battery message still persists though.
Got everything put back in. Unfortunately the dreaded battery icon / Visit Workshop alarm is still coming up. This all started after I replaced the consumer battery. It was continuously losing charge, causing all kinds of issues. I replaced it with the OEM battery; that's when the battery icon started appearing. Innova scanner says there is no reset required and it does clear itself after restarting, but then quickly reappears. When I replaced the consumer battery, I didn't disconnect the starter battery, not sure if that has messed something up or not. Still searching for answers.... Also have a P0123 / P120 alarm, which is the accelerator sensor. I have a new accelerator pedal on order which should resolve that (hopefully)... Just need to figure out the batter icon alarm...
