Omarsvette

im working on my 73 rear defrost. the switch is round and on the bottom left of center console by my right knee. now my switch maybe broken cuz there is no way for the wiring harnes to connect to it. there is 11 volts coming from orange wire. nothing from purple. and yellow wire with fuse has been cut off. i ran a jump wire with a test light from orange to purple and light came on. i then ran a jump wire without a light and the rear defrost motor just clicks. any ideas? maybe the resistor on the motor? maybe bad ground? were can i get a new switch? nobody seems to make it. after work ill clean up the grounds, i ran out of time this moring but if you have any ideas let me know.