Heater fan switch needed

Does anyone have/know where I can get a heater fan switch? Its for a 66 Mustang using the old resistor method to regulate how much power goes through the ground cable. That adjusts the fan speed. Also, what years are interchangable?

http://www.paddockparts.com/Paddock...alse&mscssid=7D0D186DEB4648C7B2314FCBA0A98473

That site says 65-66, but I can't look up the part number anywhere else, so they may be in error.