kino1161

My wife has a red battery light flashing on her dash right now. It just started. What could the culprit be?

08 ML350

Maj. Dundee

Either the battery needs replacement or the alternator is not charging properly.

DavidLN

Hello:

I just went through this with my Valeo alternator. The problem with this particular alternator is the that the brushes are quite narrow and dig a groove in the slip rings. Im bought a new alternator. The install is quite straight forward. One of the quick and dirty tests you can do is reseat the brushes with a moderate tap with a mallet. I used a long extension to get onto the alternator body. One sharp hit and the brushes reseated and it charged for several minutes.

I ended up replacing the main battery and the auxiliary as well as they were both original. I installed an Odyssey 49-950. The old battery was getting pretty tired. While cranking it would go down to 8.x volts.

Dave

kino1161

I changed the main battery about a year ago. I did a test that I saw on you tube and supposedly the battery and the alternator are doing as they are supposed to. I did not and have not changed the auxiliary battery since I had the vehicle (about 7 years). Would anyone recommend I change that?

I must also note that I believe my water pump went out yesterday (at the same time) because a lot coolant leaked out yesterday. Could it be that the coolant leaked on the alternator and caused the battery light to come on?


08 ML350

Maj. Dundee

I doubt that you were able to check the battery and alternator just by looking at a YouTube video as it requires electrical equipment.

Do not replace the aux. battery. If it was faulty, you would have gotten a WHITE message in the cluster.

I do not believe that the alternator has been affected by the coolant leak. Have the leak fixed first.

kino1161

Maj Dundee, thank you, I will do just that.

FYI. the you tube video has you turn the key to the last click before starting, check the volts, then start the vehicle to see if the volts increase. Supposedly, that is suppose to tell you whether the alternator is charging the battery as is should. ???

Maj. Dundee

With the eng. off, the voltage should be 12.7v, running 14.1 or there abouts.

kino1161

I was around (if I remember correctly) 12.3, 12.4 running and 13.9 running...

Maj. Dundee

Without the eng. running, see link for state of charge.