I dont think turn signals were optional in '59. The factory manual shows wiring diagram for trun signals, but it is hard to read. If you cant read the diagram posted by Bullfoot, send me a Fax # and I will fax you a diagram I got from a vendor when I purchased a new t.s. switch.
It is not much better, but you can make out wire colors.
Did you have a specific question about the T.S?
