Help diagnosing electrical issues
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2013 W204 C63 AMG
Help diagnosing electrical issues
Hey everyone, I have been having weird electrical issues in my 2013 C63 for the past few weeks. I will be driving for 15 minutes when weird low voltage issues will arise - most common is brake hold will stop working (this happened to me when I needed a new battery). Occasionally, the red battery sign will come up. I replaced my battery back in May so battery is quite new. As it is under warranty, I had it tested and it seems fine. Car starts up perfectly fine.The other day I was driving and I got some light flickering and rough idling. It seems like the car is fine after starting but after 10-15 minutes of driving, the voltage drops.
In all, I am suspecting the alternator or the voltage regulator on the alternator. Does this sound like a case of worn brushes on the voltage regulator, or would I need a full replacement of the alt? I have heard these alternators are usually pretty sold and should not be going at my mileage. I am at 160,000km (almost 100k miles). Am thinking to get the Bosch regulator (1986AE0040), but wanted to see what everyone thought. Thanks!
In all, I am suspecting the alternator or the voltage regulator on the alternator. Does this sound like a case of worn brushes on the voltage regulator, or would I need a full replacement of the alt? I have heard these alternators are usually pretty sold and should not be going at my mileage. I am at 160,000km (almost 100k miles). Am thinking to get the Bosch regulator (1986AE0040), but wanted to see what everyone thought. Thanks!
Last edited by blech77; Oct 7, 2025 at 02:51 PM.
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12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG + Ultima Can-Am sold)
Sounds like your voltage regulator is on the way out. Cheap fix and I doubt it's the alternator
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