Reverse lights not working

[lidavef]

2005 V8 4x4 reverse lights not working. Is the switch inside the neutral safety switch or is it a separate switch? Asking so I know where to start tracing wires. Thanks

 

[drdoom]

According to the Ford shop manual for 2005 Explorer, the Digital Transmission Range (TR) Sensor completes the back-up lamp circuit.
Side of the transmission is where it's located.