votage regulator do i have internal or external

[unclemark]

Hey okay so i took my 1984 300D to o'reily's and they tested it, turns out the alternator was putting out 16.75 at idle, they said it might be a bad voltage regulator. They also said that it might have been why my headlights quit working. They didnt carry them looked on line and there are two offered internal and external. What am i looking for to tell what i have?


Also it seems to me that if my alternator was putting out that many volts why would my battery be dead. In my mind i would think that it would be charged to its max.

What has happened is that yesterday my car wouldnt start, no clicks or even a budge from the starter. Got jumped and started fine. Bought new battery installed it last night and nothing, hooked up to jumper cables and jumped off gf's car. started fine this morning at lunch nothing. Jumped again and its fine.

I'd appreciate any advice or help

thanks