7-pin versus 8-pin headlight switch - 1970 Jimmy

[Resto-Rat]

I have been working getting all my lights working and the headlights do not come on. Got a nice police escort the other night for last mile of 25 mile no headlight run at midnight.

I have studied the wiring diagrams and read all the threads.

My dinner switch is fully functional. All the wiring tests for good continuity between the NEW headlight switch and the dinner. The two 12-volt fused and unfused power hots also test positive for voltage.

When I put the old switch in headlights work fine. (But that switch has a busted reostat) Dimmer switch works beautifully for Low and High beams. All good (except panel lights from broken reostate)

When I plug new switch in, all the side marker and dash lights work, just nothing on the headlights. No power down to the dimmer switch coming out of the switch.

I have followed the testing YouTube and the switch tests good on all pins for continuity and power voltage and resistance per test instruction.

The only thing I can see is that the switch from NAPA is an 8-pin switch. And my switch and harness is a 7-pin switch. The number three and the number 7 are not used and no wire in the harness.

Is it possible that there is something unique between the 7-pin and the 8-pin switch that provides a ground or is missing something that keeps the 8-pin switch from working on the 7-pin harness? There is obviously an extra #7 spade on the switch, but no wire in the harness so just goes to air. (My old switch does not have the #7 spade.)

When I test the new switch on the bench with power jumpers the #6 headlight spade for the light blue wire to the dimmer wire gives full voltage. So I am pretty sure the switch is making the necessary contact internally.

Ideas?