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MB Paul
MB Paul, Mercedes Technician
Category: Mercedes
Satisfied Customers: 3567
Experience:  Qualified Mercedes Benz Diagnostic Technician - 20+ years experience - Workshop Foreman for Mercedes
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Battery is charged at 12.5v at on2. After ignition

Customer Question

Battery is charged at 12.5v at on2. After ignition alternator reads 14.4v with no accessories. Run the car for around 10 min and then volts drop and car gives warning signals then dies. I can only assume that it would be either the battery or alternator, but with those readings I feel it may be central computer module???? I'm guessing. Please help
JA: Have you checked all the fuses? Do you have a wiring diagram?
Customer: I have not checked any fuses. All signs including the tow truck driver points to alternator, voltage regulator, or battery.
JA: Are you fixing your MINI yourself? What have you tried so far?
Customer: I cleaned all connections between battery and alternator
JA: Anything else you want the mechanic to know before I connect you?
Customer: I learned from a website that I can check the battery and alternator and what volts they should read. Haven't seen this problem on there
Submitted: 4 months ago.
Category: Mercedes
Expert:  Chad Farhat replied 4 months ago.

Hi, I'm Chad. Welcome to JustAnswer. I'm reviewing your question and I will be posting your reply ASAP.

Expert:  Chad Farhat replied 4 months ago.

Hey how are you

1- Recheck the alternator for 14.4 volts with loads on like head lights ,radio ,ac flasher and see if you still reading 14.4 ,if you are unfortunately there is no fuse or relay the alternate regulator is, computer controlled ,but wiring and pin in connectors and star diagnostic scanner is required

Please let me know if that works for you you need anything else on it

Thank You

Chad Farhat

ASE Certified Technician

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