Alternator differences

[Radek]

Obligatory Audi content:  5-cyl in my Eurovan.
The alternator in my 93 EV is not charging, even though brushes are ok.  I have a spare alternator for my daughter's 04 Jetta - it's physically identical and fits the EV; however, there is a slight difference in the electrical connections.  The main charging wire connector is the same - a post with 13mm nut on it.  The small connector, though, is different:   a single blue wire on the EV, two black wires on the Jetta.  When I look at the broken EV alternator, there is a double connector on it as well, but only one wire goes to it.  On the Jetta, two wires go to the connector.
Can I swap the alternators?  BTW, the Jetta alternator has letters L DFM next to the small double wire connector. 
Thanks.

Radek
electrically challenged