Good question, I've been wondering the same thing, but was too lazy to research it.
According to the wiring diagram in my chiltons guide, for your 86 Ranger, the left front signal wire should be green with a white stripe, and your right front should be white with a light blue stripe. These are the wires going from your original switch to the front lamps.
Light Blue will be the wire from the flasher to the multifunction switch.
As for the rear, it gets a little confusing. Light green with orange stripe is left, and Orange with light blue stripe is right, BUT, it appears as though the brakelamp signal uses these same wires. So you would also have to bypass the multifunction switch with the brakelamp wires too, the wire coming from the stoplight switch to the multifunction switch is Light green.
Hopefully this helps a little, while the picture below is blurry, you can still kindof make out what's what.
Here is the page, not sure if you can read it though.