SL55/63/65/R230 AMG: RED BATTERY LIGHT - (probably) not a fuse issue
Thread Starter
Newbie
Joined: Mar 2022
Posts: 1
Likes: 0
2005 SL55 AMG
RED BATTERY LIGHT - (probably) not a fuse issue
2005 SL55. Not my car, parked due to terminal health issues, no service history available. Car sitting unused for about ten years. Replaced both batteries in the correct sequence with new, fully charged ones. Have 14.6v at starter battery and 14.1v at the "consumer" battery with engine idling. Is this voltage too high for the load separator? Can't find other any reason why the red light stays on. I don't have SDS on my scanner.
MBWorld Fanatic!
Joined: Sep 2007
Posts: 1,481
Likes: 310
95 SL600
The starter battery only gets charged when needed, as it only starts the car so it doesn’t need to be charged all the time the car is running. When I had a bad battery control module, the batteries both had alternator voltage and battery light was on.
Out Of Control!!
Joined: Apr 2019
Posts: 11,958
Likes: 6,802
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
charcoaled BCM...
Having good batteries and stable charging voltage is excellent way to keep high charging Amps from toasting things around.
Take a quick look at your BCM internals for evidence of troubles. I've seen charcoaled units, hopefully not yours.
Take a quick look at your BCM internals for evidence of troubles. I've seen charcoaled units, hopefully not yours.
