[b3lha]

Originally Posted by Nomake Wan

Also, this adds pin 20 or the Time Control Unit to the list of connections in the Illum circuit...

Are you looking at the diagram from the Factory Service Manual Section 6-3? Or some other diagram?

From what I can see, those lights you mentioned are always connected to power from fuse no.9 - a red wire which goes to B41 pin 7 and B80 pin 8 and B99 pin 5. You should check all these are live.
The time control unit switches these lights on by connecting the wire that goes into pin 20 (Connector B91) to ground. You could try grounding that wire yourself and seeing if the lights come on.