I have no backup lights on my ranger.I replaced clutch and slave unit about a month ago and noticed a week or so ago I had no backup lights.I have changed out the switch and still nothing,I have a Haynes manual and looked up wiring for this circuit and the wires in the diagram going to switch are a different color than mine,the manual says it it is orange and purple mine are white blk and blk white.The wires going back to bkup lights are pink blk and blk but i noticed that the other switch on the other side of tranny had blk and blk pink wires going to it .I went to Ford to find out what this switch is and said it was a gerashift position switch but nobody in the parts dept. knew what this switch actually does.If i jumper these wires going to this switch the bkup lights work in neutral but not in reverse.I have also tested new bkup switch to make sure it is working properly and it has continuity through it when tranny is in reverse.Does this circuit somehow go through the position switch ,it seems strange that it has same colored wires and I can make the lights work by jumpering these two wires I just can,t get them to work in reverse.By the way this is a 5 speed M50d 4x4 and any help would greatly be appreciated.

 

The switch you replaced is the "neutral sense switch" Look at this diagram down in the middle bottom.
http://www.autozone.com/images/cds/g...3d800f947e.gif

The wires match to your description so that must be what's going on. Looks like you need to work on or replace the other switch you found on the other side of the tranny.