I believe this is the amp pinouts for your year jetta (99% sure)
It will help for installing a new amp.

Here's the wires out of the [Monsoon] amp on the green connector:
1 + Left Rear Woofer Pur
2 – Left Rear Woofer Brn
3 + Right Rear Woofer Pur
4 – Right Rear Woofer Brn
5 + Left Rear Tweeter Blu
6 – Left Rear Tweeter Brn/Blu
7 + Right Rear Tweeter Blu
8 – Right Rear Tweeter Brn/Blu
9 + Left Front Tweeter Red/Grn
10 – Right Front Tweeter Brn/Red
11 – Left Front Tweeter Brn/Grn
12 + Right Front Tweeter Red
13 – Left Front Woofer Brn/Ylw
14 + Left Front Woofer Ylw
15 – Right Front Woofer Brn/Wht
16 + Right Front Woofer Wht
Here's the wires in (from the HU) on the grey connector
14 + In Left Rear Blu
15 – In Left Rear Brn
17 – In Right Rear Brn
18 + In Right Rear Grn
20 + In Left Front Ylw
21 – In Left Front Brn
23 + In Right Front Brn
24 – In Right Front Red