The lever on the switch travels from right to left when it faces the firewall. The trip pin also travels from right to left going from low gears to park. When shifting from park to reverse, a complete circuit is achieved and the rear backup lights come on. They will turn off when the column is shifted to drive or any other position other than reverse.
There was a member that said to use a 1/4×28×1 1/2 stud with a jam nut. Been searching all the local stores, and no one carries that size. And what size are the 3 screws to mount the switch?
So to recap, your switch should point towards the firewall and the wiring towards the driver. The switch lever is controlled by the trip pin and it moves from right to left from the driver's view- shifter moving from low gears to park. The switch has slot mounting for fine tune adjustment of the lever and corresponding electrical connection. I found it easy to set the switch lever all the way to the left (lever spring is compressed) with the trip pin holding it in place in the park position. The column was out of the car at the time I hooked up the electrical connector and shifted it to reverse, and yes, the lights came on. I them put column back in the car and re-checked to see if the lights would come on. They did and there was no need to do any more adjustments. It's kind of cramped down there so close to the firewall, but one can make those fine tune adjustment with small fingers. Hope this makes sense and helps you.