2003 E320 RED BATTERY LIGHT COMES ON DASH
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2003, E320
2003 E320 RED BATTERY LIGHT COMES ON DASH
RED full background in the center of the speedometer displaying a BATTERY and underneath it also displaying temperature and mileage.
( with NO messages like : Battery/Alternator Visit Workshop ! OR Undervoltage Charge Battery )
Hi fellows, over a week ago I noticed the "Red Battery Light" showed up on my dash. ( I own this car for a few years now and had no electrical issues, she is my summer toy and in the winter it is on battery charger tender.)
Measured the Battery voltage ( with my multimeter ) in the trunk and it was 11.7 Volts, started the car it read 12.30 Volts ( Battery stamped 2006).Bought a new Mercedes battery and installed it myself. Measured the voltage ( with my multimeter ) it was 12.56 Volts, started the car and right off the batt the "Red Battery Light" appeared again !!!!. Pressed up/down arrow on the steering wheel and light went out. Measured the voltage while car on, read: 13.72 Volts. Drove the car here and there, high way drive , stopped here and there, etc etc...no more "Red Battery Light" any time I started the car and car drove nice and smooth...
Parked the car, sat in the garage for 17 hrs, decided to use it, started the car "the Red Battery Light" showed up. This time I used on dash UB reading and it read: 14.2 V
turned off the car, UB: 12.7 V.
Anyhow, decided to drive and monitored the UB voltage it was at 14.2 Volts, again no issues with the ride, nice and smooth...
So, here is the question: Why while alternator charging the good/healthy battery still I get the Red Battery Light when the car sitting in garage let's say around 15 hrs?
Thanks a lot.
( with NO messages like : Battery/Alternator Visit Workshop ! OR Undervoltage Charge Battery )
Hi fellows, over a week ago I noticed the "Red Battery Light" showed up on my dash. ( I own this car for a few years now and had no electrical issues, she is my summer toy and in the winter it is on battery charger tender.)
Measured the Battery voltage ( with my multimeter ) in the trunk and it was 11.7 Volts, started the car it read 12.30 Volts ( Battery stamped 2006).Bought a new Mercedes battery and installed it myself. Measured the voltage ( with my multimeter ) it was 12.56 Volts, started the car and right off the batt the "Red Battery Light" appeared again !!!!. Pressed up/down arrow on the steering wheel and light went out. Measured the voltage while car on, read: 13.72 Volts. Drove the car here and there, high way drive , stopped here and there, etc etc...no more "Red Battery Light" any time I started the car and car drove nice and smooth...
Parked the car, sat in the garage for 17 hrs, decided to use it, started the car "the Red Battery Light" showed up. This time I used on dash UB reading and it read: 14.2 V
turned off the car, UB: 12.7 V.
Anyhow, decided to drive and monitored the UB voltage it was at 14.2 Volts, again no issues with the ride, nice and smooth...
So, here is the question: Why while alternator charging the good/healthy battery still I get the Red Battery Light when the car sitting in garage let's say around 15 hrs?
Thanks a lot.
Last edited by Handyman101; Sep 7, 2022 at 09:32 PM.
Out Of Control!!
Joined: Jul 2003
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From: North Scottsdale, AZ
'71 Pinto
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2003, E320
Could be BCM: https://mbworld.org/forums/e-class-w...ml#post8628493
Thread Starter
Junior Member
Joined: Aug 2022
Posts: 17
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2003, E320
Thread Starter
Junior Member
Joined: Aug 2022
Posts: 17
Likes: 0
2003, E320
So now that I know there are two batteries, it means I have to buy another battery/charger/tender for the small one as well? hmmm
2) Thanks a lot for the good quality/ colorful pdf. Definitely I will go thru that as well.
btw, mine does NOT show this messages:Battery/Alternator Visit Workshop ! OR Undervoltage Charge Battery
Only an icon of a battery in full red background !
Last edited by Handyman101; Sep 7, 2022 at 09:35 PM.
