1995 s320 w140 battery light questions
 

Hi,

Car: 1995 s320 with 300k miles.
Symptom: battery light on when driving, turned off when applying brake, did this for two weeks, then the other day it hit limp mode.

I checked the battery voltage this morning while the car was off and had been so for two days, 12.3V. I think that's okay, right?

The manual states the light may be a result of a broken belt of sorts (I don't know the exact term, manual is at home atm). Inspected under the hood, and don't see any broken belts.

Searching the forum reveals I may need to either replace the voltage regulator or the alternator. Before going down this route, can someone tell me where to check voltage for the alternator, and anywhere else besides the battery? Pictures would be totally helpful, I'm still learning. A picture of the voltage regulator location would be awesome, too.

Thanks for your time!