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Hey i thought i had a problem with the alternator on my c300 i would get a battery light and command shutting off and my fan would stop blowing i check my voltage and amps and my amps would go -50 and never go up and my volts would go down but occasionally my amps reach +50 and my volts would charge up anyone know what the problem is its not the battery or alternator any help?
Yeah I’ve test everything and no the car completely died won’t turn over or anything lights and dash come on brand new battery brand new alternator do you think a fuse went in the positive battery fuse box
Yeah I’ve test everything and no the car completely died won’t turn over or anything lights and dash come on brand new battery brand new alternator do you think a fuse went in the positive battery fuse box
It's the negative cable it has a voltage smart regulator attached
When sensor is bad it doesn't send a signal to alternator regulator to turn on,
Which causes battery to run down.
use a voltage multimeter and measure charging voltage
it should be anywhere between 14.5 to 14.8 when properly charging .
atached multi meter on to negative cable for reading
if the battery is dead recharge battery and try to start
if battery is fully charged then you have other major issues going on .
As you stated earlier check fuses.
EIS ISSUES POSSIBLY.
Check every single ground point on the underside of the vehicle for corrosion/greening copper. Ground points screwing up will really mess with the electrical
After reading all the threads, I could not see what is the solution on this issue.
Someone could share it with me, please.
Thank you very much.
Measurement:
Mine is MB C200 W204 Year 2012 (engine M271) I turned on the fancy feature to monitor the Voltage and Current on the dashboard: - Initial battery voltage: 12.4V (I use new AMARON battery in July 2020) - A while after starting the engine, the voltage drop to 11.1 V for ver short time( I think this is normal) - Afterward, the voltage increase and reach 14.8V (current 19 A) - I start to turn on the radio, AC, and finally all lights, the voltage drop to 13.1 V (current drop to 3A) - Shift the automatic tranmission lever from P to R, the voltage drop to 12.8 V (current drop to -5.5A) - Shift again the automatic transmission lever from R to N, the voltage increase to 13.V (the current going up to 9A) - Shift again the automatic transmission lever from N to D, the voltage showing 13 V (the current drop to 2A) - Shift back again the automatic transmission lever from D to P, the voltage showing 13.6 V (the current drop to 10A)
After driving the car for about five minutes, the red engine warning light flashing and later car stall After turn off everything, I ignite again and the engine is OK. But the car will stall again after driving a while (like 5 minutes).
Do I need to replace the alternator for sure? Thank you
03-24-2019, 11:32 PM
