i have a 1990 uk mk1 and the passanger side headlight just refuses to give me anything. when its on all i get is a really weak orange glo of the filiment after a bit of revving i get some light but then it dies off again, i have tried 3 bulbs now to to rule out bad bulbs.
It could be the wiring loom where it comes out of the pop up body, It gets repeatedly flexed there by the raising and lowering of the light, So the strands within the wires may be breaking up.