2007 e320 battery drain
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2007 e320
2007 e320 battery drain
I have a problem with the battery draining causing other issues
When I start the car (and it always starts), everything seems normal for a few seconds and then ...
Engine fan starts running at full speed
Tachometer stops working
Speedometer stops working
fuel gauge stops working
engine temp stops working
windshield wipers stop working
turn signal stop working
heated seats stop working
seat belt warning stops working
gear selector lever position and program mode (main odometer display) stops working
sometimes the multifunction display works (if it goes out, the check engine light will come on at the next start -- if it doesn't go out, no CEL)
I let the engine run for 5-10 minutes in this condition, then turn it off, pull the key out. Next I start the car again and it all works.
I replaced the alternator over thanksgiving (carquest reman) which come to find out isn't compatible as it wouldn't charge. The mercedes alternator worked of course. The battery is a walmart battery that was replaced in March 2018 and it tests good.
The only thing that doesn't work since I bought the car 5 months ago is the front over head light unit / sunroof and the battery drain started in the last two months.
Last night I tried removing fuses (command, nav, and anti-theft) and the connector on the negative connection, but I had the same problem this morning. I am seeing the battery current (car off) as high as 8 amps (initially after connecting the DVM in series with the negative terminal and the body) and as low as 0.1 amps after 10-15 minutes.
I am at a loss and don't want to pay the dealer to diagnose it for me. Thoughts on ways to troubleshoot?
Thanks,
John
When I start the car (and it always starts), everything seems normal for a few seconds and then ...
Engine fan starts running at full speed
Tachometer stops working
Speedometer stops working
fuel gauge stops working
engine temp stops working
windshield wipers stop working
turn signal stop working
heated seats stop working
seat belt warning stops working
gear selector lever position and program mode (main odometer display) stops working
sometimes the multifunction display works (if it goes out, the check engine light will come on at the next start -- if it doesn't go out, no CEL)
I let the engine run for 5-10 minutes in this condition, then turn it off, pull the key out. Next I start the car again and it all works.
I replaced the alternator over thanksgiving (carquest reman) which come to find out isn't compatible as it wouldn't charge. The mercedes alternator worked of course. The battery is a walmart battery that was replaced in March 2018 and it tests good.
The only thing that doesn't work since I bought the car 5 months ago is the front over head light unit / sunroof and the battery drain started in the last two months.
Last night I tried removing fuses (command, nav, and anti-theft) and the connector on the negative connection, but I had the same problem this morning. I am seeing the battery current (car off) as high as 8 amps (initially after connecting the DVM in series with the negative terminal and the body) and as low as 0.1 amps after 10-15 minutes.
I am at a loss and don't want to pay the dealer to diagnose it for me. Thoughts on ways to troubleshoot?
Thanks,
John
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2007 e320
Battery drops 1.6V
Why does the battery drop to 12.5v immediately after turning off the ignition? I have a video of it but it won’t upload.
Using the key in position 1 and push R three times to get the voltage display. When running the UB is 14.1v but it drops immediately to 12.5v even after driving for 20 minutes. Shouldn’t it be over 13v or is this an artifact of an AGM battery?
While starting I see the voltage drop to 10v. Again I have a video but it won’t upload. Ugh!
Using the key in position 1 and push R three times to get the voltage display. When running the UB is 14.1v but it drops immediately to 12.5v even after driving for 20 minutes. Shouldn’t it be over 13v or is this an artifact of an AGM battery?
While starting I see the voltage drop to 10v. Again I have a video but it won’t upload. Ugh!
Thread Starter
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2007 e320
Narrowing it down
This weekend I checked the grounds, fuses, and reseated connectors. I also read the old threads about similar issues. The main theme I saw was to disconnect the power seat modules (under each seat) and pull fuses 6, 26 and 28. So I decided to give that a try.
I left it parked outside last night and it started right up this morning even though it was about 30 degrees F.
Guess I will start by putting the fuses back to see if it is the power seat modules.
I left it parked outside last night and it started right up this morning even though it was about 30 degrees F.
Guess I will start by putting the fuses back to see if it is the power seat modules.
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Joined: Feb 2014
Posts: 6,190
Likes: 1,550
From: MA
2008 E350 4Matic, 2011 E350 4matic
Why does the battery drop to 12.5v immediately after turning off the ignition? I have a video of it but it won’t upload.
Using the key in position 1 and push R three times to get the voltage display. When running the UB is 14.1v but it drops immediately to 12.5v even after driving for 20 minutes. Shouldn’t it be over 13v or is this an artifact of an AGM battery?
While starting I see the voltage drop to 10v. Again I have a video but it won’t upload. Ugh!
Using the key in position 1 and push R three times to get the voltage display. When running the UB is 14.1v but it drops immediately to 12.5v even after driving for 20 minutes. Shouldn’t it be over 13v or is this an artifact of an AGM battery?
While starting I see the voltage drop to 10v. Again I have a video but it won’t upload. Ugh!
https://modernsurvivalblog.com/alter...-charge-chart/
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Thread Starter
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2007 e320
This weekend I checked the grounds, fuses, and reseated connectors. I also read the old threads about similar issues. The main theme I saw was to disconnect the power seat modules (under each seat) and pull fuses 6, 26 and 28. So I decided to give that a try.
I left it parked outside last night and it started right up this morning even though it was about 30 degrees F.
Guess I will start by putting the fuses back to see if it is the power seat modules.
I left it parked outside last night and it started right up this morning even though it was about 30 degrees F.
Guess I will start by putting the fuses back to see if it is the power seat modules.
Any suggestions for a great independent in the NE DFW area?
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2007 e320
That would be the normal voltage. A fully charged battery at 70 degrees with no load should be at 12.73. Of course when it's hooked up to a car, it has a load so you're not going to see 12.73. The alternator has to output 14 volts in order for it to charge the battery. When you start the car, there's going to be a high current draw so of course the voltage is going to drop.
https://modernsurvivalblog.com/alter...-charge-chart/
https://modernsurvivalblog.com/alter...-charge-chart/
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Joined: Feb 2014
Posts: 6,190
Likes: 1,550
From: MA
2008 E350 4Matic, 2011 E350 4matic
Did you check the voltage before starting the car? Check after you shut it off and before you start it.
Do you have a battery charger? If the battery is half dead, just driving the car around won't fully charge it. But 12.5 sounds like a pretty decent state of charge, but the battery might not be able to put out enough current. You could also get the battery load tested at an auto parts store, they normally do it for free. I was also thinking that maybe your alternator might be bad, but if you replaced it with the right MB part, then in theory it should be fine. At one point there were 3 different alternators for the same car and there's many old threads of people swapping alternators til they got the right one. Also sometimes rebuilt alternators are bad out of the box, but you'd think that an MB one would be good. Otherwise if it's not those two, then you have some mysterious drain somewhere and those are the worse to track down.
Do you have a battery charger? If the battery is half dead, just driving the car around won't fully charge it. But 12.5 sounds like a pretty decent state of charge, but the battery might not be able to put out enough current. You could also get the battery load tested at an auto parts store, they normally do it for free. I was also thinking that maybe your alternator might be bad, but if you replaced it with the right MB part, then in theory it should be fine. At one point there were 3 different alternators for the same car and there's many old threads of people swapping alternators til they got the right one. Also sometimes rebuilt alternators are bad out of the box, but you'd think that an MB one would be good. Otherwise if it's not those two, then you have some mysterious drain somewhere and those are the worse to track down.
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2007 e320
Did you check the voltage before starting the car? Check after you shut it off and before you start it.
Do you have a battery charger? If the battery is half dead, just driving the car around won't fully charge it. But 12.5 sounds like a pretty decent state of charge, but the battery might not be able to put out enough current. You could also get the battery load tested at an auto parts store, they normally do it for free. I was also thinking that maybe your alternator might be bad, but if you replaced it with the right MB part, then in theory it should be fine. At one point there were 3 different alternators for the same car and there's many old threads of people swapping alternators til they got the right one. Also sometimes rebuilt alternators are bad out of the box, but you'd think that an MB one would be good. Otherwise if it's not those two, then you have some mysterious drain somewhere and those are the worse to track down.
Do you have a battery charger? If the battery is half dead, just driving the car around won't fully charge it. But 12.5 sounds like a pretty decent state of charge, but the battery might not be able to put out enough current. You could also get the battery load tested at an auto parts store, they normally do it for free. I was also thinking that maybe your alternator might be bad, but if you replaced it with the right MB part, then in theory it should be fine. At one point there were 3 different alternators for the same car and there's many old threads of people swapping alternators til they got the right one. Also sometimes rebuilt alternators are bad out of the box, but you'd think that an MB one would be good. Otherwise if it's not those two, then you have some mysterious drain somewhere and those are the worse to track down.
My bet is a mysterious drain. MB dealership replaced the alternator after I did it myself with a Advance Auto Parts remanufactured alt that wouldn’t talk to the car.
I have had the battery load tested 3 times (once at the dealership).
Tonights example: After driving about 20 minutes with the car showing 14.2v (turn key to position 1 and push R three times and voltage shows up in cluster). Turn the car off to position 1 and UB immediately drops to 12.7v. Turn key off and use remote to lock the doors. Come back out to the car 5 hours later and car shows 12.2v with key in position 1. When starting the car I see it drop to 10v and back to 14v when the car starts and the alternator kicks in. The car always starts (as long as I drive it daily or disconnect the negative battery terminal after stopping). It never struggles to start either. I guess the battery pull down at start is too much for the computers to initialize properly.
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Joined: Feb 2014
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From: MA
2008 E350 4Matic, 2011 E350 4matic
Yeah. I'm leaning toward mysterious drain that you need to track down. Keep pulling fuses if you don't want to pay for the dealer to track it down. Bluetooth uses power too but it's always on and it should only be a small amount. I will get about 12 volts when shutting it down and then when I come out to start it the next day or two it's down to maybe 11.8, but that's in cold weather. That half volt drop is a lot more than just a little bit. Hope you get it fixed soon, those deep discharges aren't good for the battery either.
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2007 e320
Yeah. I'm leaning toward mysterious drain that you need to track down. Keep pulling fuses if you don't want to pay for the dealer to track it down. Bluetooth uses power too but it's always on and it should only be a small amount. I will get about 12 volts when shutting it down and then when I come out to start it the next day or two it's down to maybe 11.8, but that's in cold weather. That half volt drop is a lot more than just a little bit. Hope you get it fixed soon, those deep discharges aren't good for the battery either.
Before starting i have 12.2v with the key in position 2. During starting I have 10.4v with the key in position 3.
Last edited by octobercar; Dec 10, 2018 at 08:35 PM.
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From: MA
2008 E350 4Matic, 2011 E350 4matic
Mine also drops to the 10v level. Not sure exactly what the number is because it's so brief it goes right back up after it starts. But when it's at 11.8, that's the same voltage whether it's sitting for one or two days, doesn't really drop anymore.
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2021 V167
I have a 2003 E500 Wagon which had a mystery drain as well. After some extensive troubleshooting, checking components with the Xentry the long and short of it came down to two things. Alot of folks have problems with the seat control modules, (which you can ditch the always hot line), and also the buttons below the radio can be an issue. For me replacing a marginal aux battery (under cabin air filter) and removing the CD from the rear cargo compartment NAV system worked. I monitored it in the garage for 24 hr periods and it would have a intermittant 30amp load. Not sure if the main battery disconnect was trying to make up for the aux battery lack of load amps or what.
Also you need to load test that aux battery not just check voltage. Mine read 12.7 v but had no amps when loaded up.
Stay persistent! You can fix it..
Also you need to load test that aux battery not just check voltage. Mine read 12.7 v but had no amps when loaded up.
Stay persistent! You can fix it..
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2006 E320 CDI
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'71 Pinto
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From: USA
2006 E320 CDI
yes Unfortunately not included for the 06. Somewhere I thought read that to b95 came out for MY06 it had a date of 53105, but now I can’t find that document so I must’ve misread something.
Ok about Documentation for the 06 something is not correct in that document. It says to be careful With the DVM because locking current is around 20 A. The specified meter fluke 23 only goes up to 10 A before it pops the fuse in the meter.
it says set the meter to the highest current range.
but without interrupting power, but you can’t connect the meter in the current mode without interrupting power.
does it actually mean set the meter to read voltage to measure voltage drop?
I guess I need to see a schematic of how that attachment point one works or look in the trunk.
Rereading the document again says bridge the meter, which will interupt the power. Poor choice of wording I guess, but still the locking of the doors is going to pop the 10a fuse.
Ok about Documentation for the 06 something is not correct in that document. It says to be careful With the DVM because locking current is around 20 A. The specified meter fluke 23 only goes up to 10 A before it pops the fuse in the meter.
it says set the meter to the highest current range.
but without interrupting power, but you can’t connect the meter in the current mode without interrupting power.
does it actually mean set the meter to read voltage to measure voltage drop?
I guess I need to see a schematic of how that attachment point one works or look in the trunk.
Rereading the document again says bridge the meter, which will interupt the power. Poor choice of wording I guess, but still the locking of the doors is going to pop the 10a fuse.
Last edited by ot1; Dec 21, 2018 at 01:06 AM.
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2007 e320
Starter?
Would a “bad” starter cause the voltage to drop to 10v while starting? I doubt it has been replaced. Thoughts?
Supposedly the battery drain has been fixed after replacing the module under the dash that controls the waking up of the other modules.
Supposedly the battery drain has been fixed after replacing the module under the dash that controls the waking up of the other modules.
Last edited by octobercar; Dec 24, 2018 at 06:06 PM.
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2007 e320
Solved
Dealer replaced gateway module because it was corroded. Still didn’t fix the dash from shutting down. Ran STAR again and found that the modules were shutting down because even though the car was running, the modules thought it was off. Turns out that replacing the key fob with a new one fixed the problem. Weird!!!
Now I have to buy a new key (metal) because the key fob was redesigned to have the locking pin on the opposite side.
I appreciate all all the help I got from y’all.
Now I have to buy a new key (metal) because the key fob was redesigned to have the locking pin on the opposite side.
I appreciate all all the help I got from y’all.
