I wanted to convert my 69 Roadrunner to air grabber setup so I purchased a 3 speed wiper motor to swap out my 2 speed unit. I purchased a new wiring harness for under hood and everything plugged in fine. I was told the dash switch would just plug into the existing wiring but the terminals are different on the back of the switches. Did I just purchase the incorrect switch or did I get incorrect information on the interchange? Any suggestions?