On the 1987 XJSC I have, the driving lights do not come on when master light switch is turned to that position. I have ran the electric and everything has current where and when it is supposed to. The lights themselves, I have jumpered power to them and they operate.
All fuses have been replaced with their AGC equivalent, and all light relays and hibitor relay have been checked and tested for contacts and operation.
The only thing I can figure out is that the lights wiring is not connected to the #1 fuse as they show to be. Does anyone know where they may run to in the main wiring loom? I do not really want to unravel the loom trying to find the unconnected ends. My other choice is to simply run another wire from the fuse block to the lights. I would rather keep this original, with the exception of them actually working.

 

US spec cars of that period were wired so that the fog lights didn't work. It's not just your car, it was all of them. Doent make sense, but that's the way it was. It's explained, and the fix described, on page 640 and 641 of "The Book" under the headlight wiring topic, available here:
http://www.jag-lovers.org/xj-s/book/XJS_help.pdf

 

I have Kirby Palms XJS book, unfortunately reconnecting the RY wire from Fuse #1 to #6 did not make any difference. I did finally find my problem, the RY wire from fuse #1 was not connected in the kick panel (LHD side) where it feeds through into the outer wiring harness. I ran continuity checks on the RY wire until I found the section where it was not feeding any current.

Next up is the Speed Control Solenoids and sealing the rubber boot.