Jetta headlights won't come on

find the low beam light relays
by law the fog lights can only come on with low beam
using fog lights on high beam is *******

If high beams work and low beams do not, then it is probably the high/low relay. It is part number 15016745 and has four prongs. To test if your relay has gone bad locate the relay in your fuse box. There will be two of these relays located next to each other. One controls the low beam headlights and the other the cooling fan. Swap the relays and check your low beam headlights. If the low beams work you have a bad relay.

Try changing the headlights....some headlight high beams will work even when the low beams dont

check the bulbs first and also the fuses theres a fuse for each side and for low and high beams, start there, good luck.

high low switch is gone or both low beams bad

Check the headlight relay.

First place to start is with headlight switch. I did have a case many years ago when both high beams were blown out at once, but this is rare. When you have the headlight switch out, jump power from te low beams to the high beam contacts. If high beams come on, replace switch.
Bill

the headlight fuses are always the first four going from left to righ on a volkswagen 1 for left lowbeam rigth low beam left high beam right high beam.