SL/R230: Battery Light On 2003 SL500
Thread Starter
Member
Joined: Nov 2009
Posts: 151
Likes: 6
From: Central Mass
2003 SL500, 2016 F250, 2017 Jeep Renegade
Battery Light On 2003 SL500
I Replaced the Rear Battery, I did the correct battery reset. Once the Baterry reset is done I can drive the car with no warning on dash. It seems after driving for some time say 1 hour I shut car off restart it and have dreaded Read Battery Icon. I do have a SDS on its way, thou I dont know how to use it quite yet or what to do with what ever it gives me for code's. I'm looking for some advise.
With car running
Front Battery is 14.73 V
Rear Battery is 14.23 V
One other thing to add not sure if it started this after I pulled this dumb move but some how I reversed the wire hookup for the trickle charger. But the instructions had said it had reverse polarity shut off. Hoping I didnt blow something.
With car running
Front Battery is 14.73 V
Rear Battery is 14.23 V
One other thing to add not sure if it started this after I pulled this dumb move but some how I reversed the wire hookup for the trickle charger. But the instructions had said it had reverse polarity shut off. Hoping I didnt blow something.
Last edited by cadbob; Dec 26, 2014 at 05:38 PM.
Thread Starter
Member
Joined: Nov 2009
Posts: 151
Likes: 6
From: Central Mass
2003 SL500, 2016 F250, 2017 Jeep Renegade
I used the SDS DAS Software, but seems Trickle Charging till batteries are fully charged also get rid of the symbol. The problem is it keeps coming back for me. Not sure what is causing it yet.
Super Member
Joined: Jul 2014
Posts: 992
Likes: 245
From: Tucson, AZ
'20 X5 M50i; '17 Ram 3500; Golf Cart; Bikes; Scooters
Save that alternator!
The regulator in the back of the alternator is most likely the culprit. There is a set of carbon brushes that wear over time. You can replace this part on the back side for less than $50, and it will likely work like new. I did mine as a preventive measure while working through the same issue. Eventually replaced the rear battery and all is well.
Junior Member
Joined: Aug 2008
Posts: 65
Likes: 1
From: Houston, TX
2003 SL500, 1998 E320 Wagon
The regulator in the back of the alternator is most likely the culprit. There is a set of carbon brushes that wear over time. You can replace this part on the back side for less than $50, and it will likely work like new. I did mine as a preventive measure while working through the same issue. Eventually replaced the rear battery and all is well.
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Newbie
Joined: Apr 2015
Posts: 2
Likes: 0
From: Leominster MA
2003 sl500
Hey guys. I am having the red battery light warning as well. Replaced the rear battery summer 2014 and kept it charged over the winter. At the end of 2014 got the red warning light. The front battery reads 12.5 volts all diconnected and when load tested reads 94%.
Hook everything back up and run the car the voltage reads 14.7v. The car starts and runs fine, no problems. Someone suggested the altenator could be a problem. any suggestions?
Karl
Hook everything back up and run the car the voltage reads 14.7v. The car starts and runs fine, no problems. Someone suggested the altenator could be a problem. any suggestions?
Karl
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Thread Starter
Member
Joined: Nov 2009
Posts: 151
Likes: 6
From: Central Mass
2003 SL500, 2016 F250, 2017 Jeep Renegade
I went through swapping parts, as SDS did not give any indications on what was bad. I started with the Battery, than checked fuses by passenger foot well, than relay next to Battery Control Module, than Alternator, and Finally replaced the cure the Battery Control Module!
Last edited by cadbob; Apr 19, 2015 at 08:42 AM. Reason: add
Thread Starter
Member
Joined: Nov 2009
Posts: 151
Likes: 6
From: Central Mass
2003 SL500, 2016 F250, 2017 Jeep Renegade
you can check the floor board fuses, check the alternator after pulling is best, the relay is 12.00, than leave Battery Control Module, and or EIS. But SDS was giving me diagnose to check fuse and and something else, but it was sort of mis-leading as BCM was not doing it's job and I got interment Battery Light on dash. No More now! 
I was seeing RED like dash everytime it came on and thought i had fixed.
I was seeing RED like dash everytime it came on and thought i had fixed.
