69 B-body reverse light troubleshooting

[hemi68charger]

Hello gang..
trying to troubleshoot why my reverse lights aren't working on the Daytona. Based on the wiring diagram, the black and violet colored wires coming from the neutral safety switch go into the bulkhead connector on the upper connector at positions 3 and 4. On the back side of the bulkhead, both wires are white, one going back to the rear of the car and the other to the radio... radio?

So, what is the purpose of the black wire in the 3-wire connector at the safety switch? Does the switch just ground when it is positioned in reverse? I would have thought the reverse light assembly grounds itself at the rear and the violet wire "feeds" current to the lamp assemblies...

thoughts?

Thanks in advance

[John_Kunkel]

The center wire on the NSS supplies a ground for the starter relay when the shifter is in P or N. One of the two outer wires is keyed power and the other goes to the bulbs in the rear which are grounded by their bases.

With the connector removed from the NSS and the ignition switch in RUN, use a test light to check for power at one of the outer wires. If no power check the fuse. 

[hemi68charger]

Checked it.. Black wire has power and when I jump it ( black to violet ) with ignition 1 on, the lights come on.... sooooooo, I must have a bad connection at the NSS. The starter relay works, so I am suspecting a bad connection....  I will try to jump the wires down there since the daytona is on jack stands...  It is a brand new NSS, but that doesn't always equal "good".