Won't crank

The switch in the trannie indeed does both the Neutral Safety and the reverse light funciotnn, but they are 2 separate switches in the same package. One can fail and the other be OK. Plus the NSS depends on linkage alignment.

Here is a way to troubleshoot that does not require a voltmeter or test light:

1. Put a jumper to ground from the post on the starter relay that has the wire to the NSS (a brown-yellow wire) and see if it starts. If so, then the issue is in the NSS.

2. If not, then it is in the relay or the wiring to the relay. Remove the small dark green-red wire (and it might be a yellow wire) from the starter relay and jump 12 volts direct to that terminal. If it starts, the relay is good. If not, replace relay.

3. If the relay and NSS are good form 1 and 2 above, then check out the seat belt interlock relay that 67Dart273 showed above. Press the bypass button once and see if it starts. If so, the seat belt interlock is the issue. Bypass that as noted.