fan switch help

[Cratos]

1970 challenger factory a/c car. all of the sudden all I have a low speed on the fan. resistor block is not burned so thinking the fan switch. are all thee terminals in play always or is it supposed to be just a
either or for the out going ?

 

[Cratos]

found an unplugged wire up under the dash about 2 inches long. ( no wonder i was hard to find)