Add "W" terminal wire to Bosch/Valeo serp-belt TDI alternator

[rodpaslow]

Yeah, I have an alternator that has the W and installed it last night - was from the 2.0 ABA.  Works fine.  I have a new VDO tach, just have to set the pots later today and also has a potentiometer so if it's off a bit I can adjust it.  I bought a cheap china electronic hand held tach, Just add a piece of it's reflective sticker to the crank and it tells speed - seems like it works well enough.  Will adjust the VDO to match it - cause I hate not having a tach.

Thanks for the help!

[rodpaslow]

I now have a working tach -  current idle is about 786, by my cheap china hand held, so I set it to just below the 800 mark.

W alternator is so much easier than finding a winding before the doide on this type of alternator - in my opinion.  I'm have virtually no electronics experience ...

[rotaecho]

I'm also getting ready for a mTDI (AHU) conversion in my Westy as well and was looking for an alternator that would mount to the block that would accept the W terminal.

Reading this post the AL0184X would be a good way to obtain the W terminal.

I have the following questions:

Does this alternator have the same/similar RPM setups for the diesels?

What is required for getting the proper Tach RPM's setup for an mk2 (CE1 diesel tachometer?) configured properly for RPMs? Should an m-TDI AHU idle around 750?

Thanks! Really hoping to get a tachometer solution figured out for my conversion.

[vanbcguy]

I have the AL0184X on mine... Works fine.

The tach you have should just plug in and work if it's for a diesel.  No magic... Not sure if there is an adjustment on those older ones, I don't think there is.  The tach will be approximately right though.

[libbydiesel]

There is an adjustment pot in the circuit of each of the tachs back to mk1.

[rotaecho]

Thanks Libby, sounds like a better option for a mTDI setup would be using the AL0184X with the W terminal. That way there's no prying off the plastic back and soldering a wire to a stock TDI alternator.

There is an adjustment pot in the circuit of each of the tachs back to mk1.

[Achilles3588]

Swapping a 1.6 TD JX for a 1.9 mTDI AFN in a '91 Syncro Doka.

The bright shiny new Bosch Alternator Model No. AL0723X that came with the AFN does not have an explicitly W signal, rather B+, D+ and finally DF. I have seen pics above of the AL0184X where the W connection is exactly where the 0723X places the DF in a two pin connector. When looking at AHU wiring schematics it appears the DF signal is effectively equivalent to the W but that's a simplified schematic and is without looking at the alternator internals or the mfr's internal schematic. Does anyone know if the connecting the JX's W wire to the alternator's DF terminal will accomplish the tach signal objective? I don't want to void the warranty on the new alternator by making the above mods.

[libbydiesel]

The AHU alternators I have used have had the W terminal as a marked connection.  I have not used an AFN alt. 

[Frankly21]

Check your brushes and if not, see maybe where the cable does not connect at the alternator, how it connects