71 W108 electrical mystery

[bracurrie]

I submit the attached photo to crowd source what the hanging plug may be and is the grounding block standard issue on a 108.018 with an M130 MFI engine?
All electrical functions are normal save the cigar lighter.

[vandor]

Just a guess, but if the externally regulated alternator was replaced with an internally regulated one, then that could be the pigtail to the old voltage regulator.

[bracurrie]

Originally Posted by vandor

Just a guess, but if the externally regulated alternator was replaced with an internally regulated one, then that could be the pigtail to the old voltage regulator.

This answer is why I love this forum, not only did I get an answer but I learned that there was such a thing as an alternator with an internal voltage regulator.
Question: What are the plusses and minuses for using IVR alternator in my car?
Brad

[vandor]

Around the mid 70s electronics got small enough that manufacturers were able to fit the voltage regulator on the alternator, so the car was simpler, there were less wires and less components, easier to build on an assembly line. The only real advantage of an IVR on an older Benz is that later alternators are generally rated a more amps, so if one converts to a later alternator it will likely have a higher output.