Alternator Bosch or OEM Volkswagen

I installed a new BOSCH alternator in my MERCEDES-BENZ 190E 2.0 1991, and unlike the old one, this one has a **D+ port, a B+ port 1, and a B+ port 2.**

This is a known issue with non OEM and especially bosch alternators, the regulator gives a different signal to the power control unit.

If you were family or my customer I would get the Bosch.

IMO a rebuilt German Bosch unit is far superior to the Chinese alts.

I’m running my a 120amp Bosch but my car is m42 it’s honestly overkill for my setup with aftermarket speakers, amp, and sub.

bosch alternator is better. get a bosch alternator.

Replaced the alternator - twice. The second one failed as a result of a jump start scorching a relay in the voltage :-( Replaced the starter (in 2024), First alternator failed at 49K miles - oddly, when the car came out of the shop, the oil light came on and they found debris in the pick up so I got a new long block (under warranty so I suspect VOA knew of some defect for that model/year). Had one strut bearing fail at about 90K miles. I also had the AC recharged - car actually came from the factory with too much pressure (would ice up on humid days). I've stuck to dealer maintenance for everything except the strut repair and the usual annual CC alignments (well documented issue...) and keep all fluids (coolant/brakes/DSG) fresh. My car is still a daily driver - I'm probably due another battery soon but it runs great. I'm tempted to freshen the struts and control arms and add a rear sway bar - and possibly a tune, but I also see a Golf R in my future! I've run 3 other cars to 250K miles (Volvo 850, Highlander and an Audi 4KQ) and I don't see any reason why the dub can't get to 200K+ particularly if you keep up with a full maintenance plan. You may need to have some carbon blasting done at 100K, have the timing chain tension and service the PCV (leaving that too long leads to the carbon build up in the DI engines) but those are like 50K mile intervals

Bought a new bosch alternator and installed it.

Everything went well, or so we thought, as he turned on the car it started to slowly smoke. I assume that the ac compressor plug got shorted or was loosely plug bc it was the hardest thing to replug and the fact the ac isn’t blowing cold air anymore. We recharged the battery to 12.4-12.5 v. The alternator was only pulling 13.3-13.7 v with load and without load. Mind you this was a new OES Bosch alternator.

supplier willing to give me a Bosch remanufactured alternator (as good faith) to compare. after installation on Bosch, the result is worse than the Denso (output at alternator at 12.5V)