Sometimes, you need to contact a vw dealer with your vin number and see, if the harness is still avaialble for order, otherwise repair or get a good used replacement part, is another option. While online catalogs can be helpful; sometimes, yoi need a professional vw parts person with access to VW's ETKA, to help you get the correct parts you need.
There are also, automotive wiring harness speciality shops; that can reproduce, rebuild or repair your existing harness, i don't know how cost effective that would be but you could ask for a estimate.
For harness damage, vw offers, repair wires with factory crimped terminals, new replacement plugs, etc. and you should be able to successfully, repair typical wiring problems.
If you want to learn correct vw factory repair standards and techniques, down load the VW wiring repair self study program for more info.