Dash lights out

[i82much]

1972 K10, factory wiring:

My dash lights are out, hoping for some help diagnosing. Rear running lights work, courtesy lamp works, and the dimmer switch correctly dims some aftermarket gauges I have wired into the fuse panel.

I pulled the connector off the back of the dash and I do not have power at the #8 terminal. So if I understand this correctly, either:

(1) The gray wire is broken between the connector and the fuse panel, or
(2) Possibly I have incorrectly wired the aftermarket gauges to the hot side of the fuse and the fuse is blown.

Does that about sum it up? Assuming the gauges are wired to the cold side of the fuse, does anyone see anything wrong with simply splicing the power wire to the gauge lights into the grey wire somewhere close to the dash connector?

Thanks!