Need help, Low battery conv functions unavailable
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Need help, Low battery conv functions unavailable
I have a 2005 E500 sedan, I've been getting "Low battery, conv functions unavailable" constantly while driving my car
Symptoms: Radio goes in and out, all dash lighting and high beams begin to slightly flicker, all cigarette lighter chargers stop working, at times windows and power seat adjustment will stop working
what i've tried: I've replaced the front aux battery with a new one, fixed nothing. Fully charged the battery, fixed nothing. Checked every single fuse in the car, none were broken. And lastly I've brought it to orileys and napa multiple times for a battery and alternator test, every time they say they're both working fine and have between 14.2-14.5 amps
Symptoms: Radio goes in and out, all dash lighting and high beams begin to slightly flicker, all cigarette lighter chargers stop working, at times windows and power seat adjustment will stop working
what i've tried: I've replaced the front aux battery with a new one, fixed nothing. Fully charged the battery, fixed nothing. Checked every single fuse in the car, none were broken. And lastly I've brought it to orileys and napa multiple times for a battery and alternator test, every time they say they're both working fine and have between 14.2-14.5 amps
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Joined: Oct 2015
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From: Merkville the galaxy of Stars
'99 CLK/05 E500 WAG
I have a 2005 E500 sedan, I've been getting "Low battery, conv functions unavailable" constantly while driving my car
Symptoms: Radio goes in and out, all dash lighting and high beams begin to slightly flicker, all cigarette lighter chargers stop working, at times windows and power seat adjustment will stop working
what i've tried: I've replaced the front aux battery with a new one, fixed nothing. Fully charged the battery, fixed nothing. Checked every single fuse in the car, none were broken. And lastly I've brought it to orileys and napa multiple times for a battery and alternator test, every time they say they're both working fine and have between 14.2-14.5 amps
Symptoms: Radio goes in and out, all dash lighting and high beams begin to slightly flicker, all cigarette lighter chargers stop working, at times windows and power seat adjustment will stop working
what i've tried: I've replaced the front aux battery with a new one, fixed nothing. Fully charged the battery, fixed nothing. Checked every single fuse in the car, none were broken. And lastly I've brought it to orileys and napa multiple times for a battery and alternator test, every time they say they're both working fine and have between 14.2-14.5 amps
R,
2Merks
https://mbworld.org/forums/w211-amg/...available.html
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From: In the Shadow of the Tetons
2013 ML350 Bluetec
14.2-14.5 AMPS or VOLTS?
Volts seems like the more likely answer from an alternator test; your alternator should easily put out a hundred amps. 14.5 is a good charging VOLTAGE.
That just says your alternator is OK.
Your main battery sucks. Change it.
It's also possible that your voltage regulator is on its way out but happens to be working fine during testing.
Do you know the maintenance history of the car? Ever had a new alternator installed? When's the last time the car got a main battery replacement?
Volts seems like the more likely answer from an alternator test; your alternator should easily put out a hundred amps. 14.5 is a good charging VOLTAGE.
That just says your alternator is OK.
Your main battery sucks. Change it.
It's also possible that your voltage regulator is on its way out but happens to be working fine during testing.
Do you know the maintenance history of the car? Ever had a new alternator installed? When's the last time the car got a main battery replacement?
Last edited by rapidoxidation; Jan 2, 2025 at 08:57 PM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,957
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
The BCM may be need investigation/ consideration...
I don't know the diagram of the various years and how W211 voltage is managed.
Last edited by CaliBenzDriver; Jan 4, 2025 at 02:43 AM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,957
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
W211 electrical distribution
Great doc has everything except troubleshooting steps...
@RocketE500
Before things go bad, make a note to never use ALTERNATOR to recharge flat batteries...
Simply use a charger!!
-- The difference is ALT put-out unlimited 150A killer current.
-- A lead-acid charger supplies limited fixed under variable voltage.
-- Once damages are done poor connections develop with oxidation.
power distribution
the BCM duties
power mgt
> TROUBLESHOOTING:
-- Everything is always possible (Batts; ALT) but these chassis are known for charcoaled BCM... focuss on that!
-- Read the chassis faults with a $150 scanner, in particular the battery mgt module
-- Test voltages under operating conditions with a DVM... poor connections will exhibit dropped voltage !!
-- Missing voltage may be linked to open fuse links.
Last edited by CaliBenzDriver; Jan 4, 2025 at 02:24 PM.
