My '65 survivor has a single speed wiper setup. I found a 2 speed motor unit with washer pump. I have been unable to locate a suitable switch to operate it. Will a switch from a '65 or '66 Impala work? What about the knob matching? I assume the washer is activated with button in center of knob.

Yes, it is. Don't know about the Impala switches, but the 64 Chevelle had two speed wipers with wash too. RichL-79 is in Nebraska too and if you look up his username and PM him, he can probably help.

M&H has the switch. You can use the link below to search. Do you have the harness? The knob should be easy to locate, try a want ad in classifieds.

http://www.wiringharness.com/modelsearchgm.htm

The wiper arm transmission from your one-speed set up will not work with a two-speed motor. The two-speed motor requires a mounting plate to mount it to the firewall. You'll also need to add the two-speed wiper wiring harness.