1999 VW Jetta passenger seat cable adjustment broke or is locked in. How do I fix?

Hello, raise the seat as high as you can for best view under seat.

Remove the plastic rail covers at the rear of the seat (see pdf)

At the front bottom of the seat, remove the two securing bolts.

Look under the seat. You will have to manually push a pin to the
side, in order for the seat to be able to slide back & out.

Once the chair is free in the front, tilt it back & disconnect the
electrical connectors under the seat.

Slide the seat all the way out and lift it out of the car.

You will need to get a replacement cable to re-attach it to the seat:

Before you order, make sure to inspect exactly what is broken.

Sorry. No PDF attached, image instead.

One more picture for you.

These images and instructions look good.