I don't have an exact answer for you because Jetta's came with a plain four cylinder (1.8L I think), a 1.8L turbocharged four cylinder, the 2.8L VR6 six cylinder, or the TDI diesel. To get a more specific answer from someone you will have to indicate your engine.
Regardless though, the alternator is driven by the serpentine belt, so if you can follow this around you should be able to fine the alternator. If you can't recognize it, you're probably not the one to put a wrench to it.
under the back passenger seet
Check your answer
front side of engine near the alternator
Begin by removing the belt from your 1994 VW Jetta alternator. Remove the alternator wiring harness. Remove the alternator retaining bolts.
I replaced mine the other day- it is under/behind the alternator.
its located in between the power steering pump and alternator when in doubt follow the ac lines that run to and from it
Remove the wiring harness from the back of your 1993 VW Jetta alternator. Remove the three alternator retaining bolts. Remove the alternator belt. Reverse the process to install your new alternator.
You will need to remove the belt from your 2002 VW Jetta alternator. Remove the wiring harness from the back of the alternator. Remove the alternator retaining bolts. Reverse the process to install the new alternator.
There is no fuse for the alternator.
Look at the front of the bracket underneath of you alternator, you will see a bolt that connects to the back of the pulley below the alternator itself. That will dial in/out your alternator and then you can tighten down the nut that holds the pulley in place. WHile it is true the tensioner is located on the top of the alternator with a dial type ratchet system, I have not had an 89-90 Jetta where this works. Usually you have to tension it with a bar of some sort prying against another pce of the engine.
You should be able to remove the alternator bracket, on your 1995 Jetta, by removing the three retaining bolts. The bracket should easily come off.
Where is the oil pan on a 1999 Jetta located?