I am having a problem getting my 1993 190e running. The battery is reading 12.5 volts right before I start it... then, when running, the voltage starts to drop. I have 2 alternators and they both do the same thing. I just bought this Interstate battery last week.


There are three places for wiring on the back of the alternator

B+
D+
and W?

What does the W hook to?

Thanks for any help