Anybody know where these wires go ?  3 prong plug. 1 white wire, 1 white with black stripe and 1 blue wire. I think it's blue, it was cut. Is it for the radio ? Thank you very much.

Check out the wiring diagrams..

http://www.classiczcars.com/files/category/1-wiring-diagrams/

Strange, I have one too in my 72 Z harness, the only male counterpart on the blower/heater doesn't look like it belongs to it. Maybe it's a left over from something on an earlier car or an earlier radio.

It's definitely for the radio. The challenge is to find a wiring diagram that shows the white and white/black wires.

Thank you very much.