Continuing to track down source of no voltage to coil while cranking

Bugman said
J3 14 br leaves ignition switch and goes to first splice, branch goes to seat belt starter interlock page 14-18 cordinates 17 E. Next to CE 2 bulkhead connector ,Next is 3 way splice page 14-15 6 E as seen in your picture

Makes sense but starter interlock on a '75 ? Could be. I'm just asking. I had a '75 without.