Now you see it, now you dont...
Andy,
If your car is an original MK-IV or W, It's supposed to be there.
You can obtain factory wiring diagrams for your car from Lectric Limited, or eBay
Fairly easy to find. The '65 service manual shows it as well. Just keep in mind that a balast is shown as an in-series resistor on the schematic. You''ll find it.
Good luck... Wiring nightmares can be tricky :eek:
Rock