Reverse lights??????

Del, Thanks. The car was orig. a auto the previous owner at one time swapped it out to a 4speed. There are no 2 violet/purple wires at bulk head. Thus confusing me some. My wiring diagram is coloured and well done and has helped me out alot. The only thing i can think of is someone has re configured a few of the wires. Im thinking of pulling the plug at column area with the violet and white that meets the 2 violet. Using the 2 violet to the black and black with white chaser to see if that works????????the only thing i can think of. Power should be with key in on position? and in reverse?