68 Camaros did not have a 4 terminal wiper motor, sounds like you got a generic one. The top connector is for the constant 12v, the lower two are for speed (depending on ground path). the switch when turned on actually controls the ground, not power. You will have to test which lower connectors work for low and high speeds. The park function is handled via a different ground path and is a longer explaination
I think maybe he mis-interpretted. There are 4 wires coming out of the Loom, and it sounds like the original plug ends were trash. Yellow is the "jumper wire that goes to both places.