In this video, I show how to replace the windshield cowl on my 2001 VW Golf. This same process will work with the mk4 Jetta as well. A piece of my cowl had cracked on the left side and broke off, causing the cowl to rattle against the windshield while driving. This was very annoying to me, so I decided to replace it. The process is pretty simple, but you might have some issues removing the wiper arms. They can sometimes bind to the wiper linkage due to corrosion. I always remove the nuts and then spray the area with a good penetrant oil......I like to use Aerokroil. I hope that this video is beneficial to you.

Aerokroil:
https://amzn.to/3ssTfcq

Wiper arm nut caps (1J0955205A):
https://amzn.to/2XPUO6o

Cowl; 1J1-819-415-E-B41

Cabin air filter plastic cover: 1J1-819-537-C-01C