I have an 83 300SD. The other day i was working on my car and a neighbor who is a mechanic, came over to say hello and he noticed a rattle sound that sounds like a spray paint bottle and said he thought that my alternator bearing was going out. A few days later, one of the belts started making a noise. A few days later the battery light came on. So before I go and remove the alternator, isn't there a way to check it?

When the car is OFF the voltage on the battery is 12.32
When the car is ON the voltage on the battery is 11.69

Also, there is a junction box where the alternator and the battery cables meet. Can't the readings here tell you if your alternator is doing it's job or not. see the attachment for a diagram of the junction box that i did real quick on word. The readings from left to right on the junction box are 0.0v, 2.37v, 10.75v, and 10.76v While the car is on.

Thanks guys, I very much appreciate your input.

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