LS Swap and NNS/Brake Light Switch

[roboticjunky]

I would use the factory NSS on the steering column since it already does the safe starts in in park/neutral and turns your reverse lights on. So you don't need the relay or extra wiring.

If your vehicle already has a neutral safety switch in the wiring harness to prevent the vehicle
from starting while it is in gear, you do not need to connect this neutral safety switch.

If don't want to use the factory set-up, then do what the manual says for the GSS-300 says and use the relay. Mount your gear selector sensor on your 4L60E just like in the manual and adjust it. I would then wire the reverse lights to the terminal on the GS-3000 that says Reverse so the lights will come on when in reverse.

https://www.dakotadigital.com/pdf/GSS-3000.pdf