Alternator going bad??

tmay_24 · 03-22-2021, 11:16 AM

Hello, I drive a 2008 328xi with a 6 speed. Lately I have been noticing a surge in anything electrical related, during idle and during normal driving, regardless of throttle and RPMs. The blower motor, headlight, and music seem to be effect the most by this. This issue has been present for the last week or two, but has been getting worse the last few days, including the headlights starting to surge and audio cutting out. I will going on a long road trip at the end of the month and figured I should get this sorted out by then. Any help is appreciated, thankyou!

e90yyc · 03-22-2021, 05:25 PM

What codes are present? If it’s an over-voltage situation there will be a DTC stored.

What do you mean by surge? Your lights become brighter and your music becomes louder? Also what’s your mileage? Any other history? You live in the States: Is that Alaska or Florida? All of these details matter and will help you get this resolved.

Beyond the need to pull codes, I would start with the basics and check voltage with a multimeter. If you don’t have one you can use the BC hidden menu to check this, but personally I would hook up my meter to battery in the trunk, turn on min/max, and go for a brief drive.

Could be voltage regulator. Fortunately that’s a cheap fix. Need more info though.

marvinstockman · 03-23-2021, 07:53 AM

You need something like this to monitor the voltage while driving:

https://www.amazon.com/Palumma-Charg...6503919&sr=8-3

JonOhh · 03-23-2021, 09:22 AM

If your OBC display is non-shitty (unlike mine) , you can enter the hidden menu, as e90yyc said. Here are some more details.

navigate to 19.00 "LOCK"

enter the sum of the last five digits of your VIN

navigate to menu 09.00 where you can monitor Voltage as seen by the cluster

For more information on how to enter the menu and how to navigate, search "e90 hidden menu" online. This is of course, assuming the cluster does not become unusable whenever the power surges. I hope this helps.

Some fluctuation is normal, though I'm not sure how much. Mine sits around 14.1-14.5 at idle, bouncing around a bit, and can briefly dip as low as 12.5 during driving conditions.

03-22-2021, 11:16 AM	#1
tmay_24 Registered 0 Rep 2 Posts Drives: 2008 328xi Join Date: Mar 2021 Location: United States iTrader: (0)	Alternator going bad?? Hello, I drive a 2008 328xi with a 6 speed. Lately I have been noticing a surge in anything electrical related, during idle and during normal driving, regardless of throttle and RPMs. The blower motor, headlight, and music seem to be effect the most by this. This issue has been present for the last week or two, but has been getting worse the last few days, including the headlights starting to surge and audio cutting out. I will going on a long road trip at the end of the month and figured I should get this sorted out by then. Any help is appreciated, thankyou!
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03-22-2021, 05:25 PM	#2
e90yyc Art Collector 2425 Rep 3,449 Posts Drives: 2007 328xi (GM-delete 6MT) Join Date: Feb 2018 Location: Canada iTrader: (0)	What codes are present? If it’s an over-voltage situation there will be a DTC stored. What do you mean by surge? Your lights become brighter and your music becomes louder? Also what’s your mileage? Any other history? You live in the States: Is that Alaska or Florida? All of these details matter and will help you get this resolved. Beyond the need to pull codes, I would start with the basics and check voltage with a multimeter. If you don’t have one you can use the BC hidden menu to check this, but personally I would hook up my meter to battery in the trunk, turn on min/max, and go for a brief drive. Could be voltage regulator. Fortunately that’s a cheap fix. Need more info though. __________________ When I'm dead, just throw me in the trash.
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03-23-2021, 07:53 AM	#3
marvinstockman Major 399 Rep 1,077 Posts Drives: 2011 BMW 328i Join Date: Aug 2015 Location: Rockville, MD iTrader: (0)	You need something like this to monitor the voltage while driving: https://www.amazon.com/Palumma-Charg...6503919&sr=8-3
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03-23-2021, 09:22 AM	#4
JonOhh Captain 672 Rep 733 Posts Drives: 06' 330i Join Date: Dec 2019 Location: Tuscaloosa, Alabama iTrader: (0) Garage List 1999 BMW M3 [10.00] 2013 Fiat 500c Abarth [0.00] 1985 Fiat/Bertone X1/9 [0.00] 2006 BMW 330i [0.00]	If your OBC display is non-shitty (unlike mine) , you can enter the hidden menu, as e90yyc said. Here are some more details. navigate to 19.00 "LOCK" enter the sum of the last five digits of your VIN navigate to menu 09.00 where you can monitor Voltage as seen by the cluster For more information on how to enter the menu and how to navigate, search "e90 hidden menu" online. This is of course, assuming the cluster does not become unusable whenever the power surges. I hope this helps. Some fluctuation is normal, though I'm not sure how much. Mine sits around 14.1-14.5 at idle, bouncing around a bit, and can briefly dip as low as 12.5 during driving conditions.
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