Mercedes charging issue
Thread Starter
Junior Member
Joined: Sep 2020
Posts: 15
Likes: 4
2011 c300 sport 4matic
Mercedes charging issue
Vehicle Information:
2004 Mercedes-Benz E320 4MATIC Sedan
VIN: WDBUF82J94X119259
Hello all,
Been having weird issues with the car as of lately. Electronics been funny; radio turning on and off, interior lights working on/off, phone charger working on/off and driving funny. Decided to start looking into this - battery voltage reading 12.5 but would fluxuate and go up from 12.5 to 13.7 and to, 14.3 but then would SPIKE to 15 - 16 and eventually to 18V. At that point, the car wouldn't go out of first gear and the battery light would jump on the dashboard.
Checking volts when the vehicle would run - the car would jump anywhere from 13.7 - 14.3 and when hitting the throttle would go up and down. My first guess here would be alternator but wanted to see what anywhere here thinks. Or, could it possibly be the voltage regulator? Is there anything else I could do as far as diagnosis before purchasing anything?
Any thoughts or opinions on this would be greatly appreciated!
Thanks!
2004 Mercedes-Benz E320 4MATIC Sedan
VIN: WDBUF82J94X119259
Hello all,
Been having weird issues with the car as of lately. Electronics been funny; radio turning on and off, interior lights working on/off, phone charger working on/off and driving funny. Decided to start looking into this - battery voltage reading 12.5 but would fluxuate and go up from 12.5 to 13.7 and to, 14.3 but then would SPIKE to 15 - 16 and eventually to 18V. At that point, the car wouldn't go out of first gear and the battery light would jump on the dashboard.
Checking volts when the vehicle would run - the car would jump anywhere from 13.7 - 14.3 and when hitting the throttle would go up and down. My first guess here would be alternator but wanted to see what anywhere here thinks. Or, could it possibly be the voltage regulator? Is there anything else I could do as far as diagnosis before purchasing anything?
Any thoughts or opinions on this would be greatly appreciated!
Thanks!
MBWorld Fanatic!
Joined: Jun 2014
Posts: 1,086
Likes: 443
From: Melbourne, Australia
2010 ML550 VIN WDC1641722A564750, 2010 B180
Typical voltages with engine running are 13.7 to 14.1V. If you're outside that range its mandatory. Becaue its a spike on the high side, it's probably the alternator's voltage regulator. That would account for the voltage spikes.
I'd also avoid driving it. Running 40% more power through the electronics on such a complicated system is looking for trouble. Conservatively, I'd be towing it to an auto-electrican for a proper diagnosis starting with the alternator and battery. You've probably cooked the battery with 18V.
I'd also avoid driving it. Running 40% more power through the electronics on such a complicated system is looking for trouble. Conservatively, I'd be towing it to an auto-electrican for a proper diagnosis starting with the alternator and battery. You've probably cooked the battery with 18V.
Last edited by BlackML550; Oct 28, 2024 at 05:46 PM.
Junior Member
Joined: May 2013
Posts: 57
Likes: 10
From: Michigan
Two 2005 E320 CDI, 2004 E500 Wagon, 2007 ML63 4MATIC
I had a similar issue with my 05CDI. The alternator was failing and was not able to regulate at low engine RPM's I would get the" convince features disabled" load shedding error on hot days while using the AC. I went with a remanufactured Bosch unit which solved the problem. My voltage now stays at 13.9-14.1 in all conditions.
Thread Starter
Junior Member
Joined: Sep 2020
Posts: 15
Likes: 4
2011 c300 sport 4matic
Thanks for the replies!
I ended up swapping in a new alternator which appears to have resolved the issue - for now. If anything changes, I'll be sure to post an update but hopefully this was the issue. Vehicle has been nothing but a nightmare since I purchased it most likely due to poor maintenece prior, nothing like the C300 I recently owned which was a blessing (nothing ever broke - ever).
Fingers crossed for now.
Sincerely,
I ended up swapping in a new alternator which appears to have resolved the issue - for now. If anything changes, I'll be sure to post an update but hopefully this was the issue. Vehicle has been nothing but a nightmare since I purchased it most likely due to poor maintenece prior, nothing like the C300 I recently owned which was a blessing (nothing ever broke - ever).
Fingers crossed for now.
Sincerely,
MBWorld Fanatic!
Joined: Jun 2014
Posts: 1,086
Likes: 443
From: Melbourne, Australia
2010 ML550 VIN WDC1641722A564750, 2010 B180
Thanks for the replies!
I ended up swapping in a new alternator which appears to have resolved the issue - for now. If anything changes, I'll be sure to post an update but hopefully this was the issue. Vehicle has been nothing but a nightmare since I purchased it most likely due to poor maintenece prior, nothing like the C300 I recently owned which was a blessing (nothing ever broke - ever).
Fingers crossed for now.
Sincerely,
I ended up swapping in a new alternator which appears to have resolved the issue - for now. If anything changes, I'll be sure to post an update but hopefully this was the issue. Vehicle has been nothing but a nightmare since I purchased it most likely due to poor maintenece prior, nothing like the C300 I recently owned which was a blessing (nothing ever broke - ever).
Fingers crossed for now.
Sincerely,
Out Of Control!!
Joined: Apr 2019
Posts: 12,002
Likes: 6,827
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
funny electricals
Today being Halloween we're allowed to speak of Gremlins openly... 👻
A welcomed step is to clean the main chassis GND strap. It is conveniently hidden all the way under the chassis near muffler at the junction of engine-tranny.
It supplies the whole car with alternator power including 800Amp starter crank... it's a mandatory maintenance item.
.🎃.
A welcomed step is to clean the main chassis GND strap. It is conveniently hidden all the way under the chassis near muffler at the junction of engine-tranny.
It supplies the whole car with alternator power including 800Amp starter crank... it's a mandatory maintenance item.
.🎃.
Last edited by CaliBenzDriver; Oct 31, 2024 at 08:46 PM.
