The TDI alternator is Bosch 120 A and is way better than the old one. The connectors that exist are B+, D+ and DF. DF is connected to the regulator on old alternators, but on these newer thingys they are a signal for the engine ECU. The only sockets that must be connected are B+ (of course) and D+ (goes to the charge warning light).
But hang on - the tachometer W connector is missing! Yes, because TDI'ed cars gets the tacho signal from a sensor at the third diesel injector.
This is easily solved though. At the back panel of the alternator there are six connections spread around the edge, each connection is a clamp with two copper wires (you can see it through the vent hole on one of the pictures). That is a W tap!
I removed the plastic cover, cleaned one of the points and soldered a cable right on to it. The tachometer is moving as expected again.
A big thanks to Adam at Frej Bildelar who sorted the wiring out for me. He's the king of car electrics!












