Oohhh, I played with my light switch for AGES.
In the end, I manfully jumped 12v to every wire (that wasn't already 12v) which plugged into the light. I also went crosseyed looking at the wiring diagrams. I think I even wrote it down, but its at home.
Ummm, what did I find. From memory:
- one wire would make the lights go on
- one made the dash lights go on
- one (or possibly two) made the parks go on - this is because the position of the indicator when the car is off will cause the parks on one side to go one (actually, on diagonal corners, but my wiring has been messed with)
It helped that my high/low beams worked too, and I knew it. My switch was dodgy.
I seem to remember (but maybe don't trust my memory?) that the yellow was the one which made the lights go on...
http://www.pelicanparts.com/911/911_Parts/Electrical/911_electrical_1973_CIS_Part1.jpg