Alternator upgrade wiring questions (with photos!) - PeachParts Mercedes-Benz Forum

renaissanceman · #1 06-02-2017, 06:54 PM

So I took a day off from work for some wrenching on my fleet of vehicles, and on the Mercedes front, I got the old FUBAR alternator out (original discussion on this thread):

It looks like the nut backed off and caused the belt to slip off the wobbling pulley. I don't know how I did not catch this, or why it would have happened! It would have probably been functional had the nut not loosened, but it was probably close time for a new one anyway. Regardless, it looks nasty now with the grooves that were cut by the fan!

I also my new alternator all tricked out with the clutched pulley:

A few questions on wiring: the original alternator has the three prong terminal connector. I can see the two large terminals are joined on the old alternator body, and marked B+, and the smaller terminal is marked D+:

What is the module in the bottom of the photo that is attached with a single phillips screw and connected with a blade connector?

In contrast, the new one has a screw terminal for B+ and D+ as well as a blade connector marked W:

From googling around, the W seems to be for an tach signal, so this is unused in my case, yes?

My question is this:
Can I just cut the harness and solder/heatshrink in the bolt on style of connection terminals. Joining the two large connectors into one and connecting to B+, connecting the smaller one to D+ and leaving W+ unconnected?

I'm not terribly concerned with keeping everything 100% original, I just want to get it working in the most reliable manner possible. The new alternator will be slightly underdriven, and I have no large electrical loads in the vehicle, so I'm not concerned with the approximately 25% additional current the alternator can supply. The upgraded alternator was appealing since it is of the more modern internal fan type. Should result in reduced noise and increased efficiency, especially with the clutched pulley.