So the other day I noticed while I was driving home in my ‘95 e320 wagon that my lights were slowly getting more dim, and clearly the battery stopped charging. Alternator is new-ish (within the past three years). As I made it home the ABS, ASR, and finally the SRS lights came on. I’m finding that the voltage at the battery is 12.5v with the car off, and 12.2v with the car on. If I connect leads to the big cable and blue wire going to the alternator with the car running I get 12.2v and 0v respectively. All fuses seem fine, including the ovp fuse. I did notice that the battery light on the cluster does not light up at all. I only get the ABS, ASR, and SRS light when I turn the key to the check position. The ABS and ASR lights turn off quickly accompanied by a relay clicking sound. The car still starts with a charged battery, and everything else seems OK. I have heard if the cluster light blows, it kills the charging system. Is this the culprit or does anyone have any additional advice based on my symptoms?

I'd say there is a 99.9% chance your voltage regulator is the culprit. It is on the back of the alternator, held in place by two screws.

Good luck

Jayare

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Do you hold seances; the OP did not identify the vehicle?

Sorry my mistake, it’s a 1995 e320 wagon.

If the bulb is out, the alternator has no field current, and won’t Charge until rpm is very high.
I’d open the cluster, and swap a bulb from somewhere else, and see if it solves the charging issue.

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Yup. It always comes as a surprise that the bulb is actually a critical part of the charging circuit. You need to replace the bulb, and not with an LED.

So I noticed that when I disconnected the battery and re-connected it, all the check lights started functioning again. So decided to remove and inspect the alternator which turned out was toast, voltage regulator brush had lost its connection. I had replaced it in the past with one from a local auto parts store, but seems to have been a poor quality unit unfortunately. Getting a new Bosch unit and will see if that fixes the issue.

i have same problem,