Last electrical question

[Bwword]

I recently purchased a 1973 with the 400 4 barrel carb. I have worked out most of the electrical issues with the help of the shop manual / wiring diagrams. I am still stumped regarding the circuit #5 on the fuse block - the one with the 5 amp fuse that feeds the lights to the instrument cluster.  I have no power in this circuit and no power when testing a new fuse at the fuse block connectors.  The other 7 fuses (20amp) all have power. Any ideas?
Thanks

[Gold Rush]

OK, let me see if I can shed some light (no pun intended) on this....

Power to the circuit comes from fuse #4 to the head lamp switch.  When the switch is pulled out it passes that power on to the variable resistor controlling the dash lights and a couple other places.  With the switch knob fully counterclockwise (not in detent position) power is supplied to fuse #5.  By turning the knob just slightly clockwise less power is sent to fuse #5.  The further clockwise the knob is turned less and less voltage is applied causing the lights to dim down.

I hope that helped.