Scott, it's hard to say if it is the switch or the wiper. Your issue is similar but different. The way I checked my unit out was to find out what conditions should be on the wiper pins in the off, low, and high positions. Then I disconnected the switch from the wiper (all three wires, two connectors) and checked each connector while turning on the ignition and moving the switch from off to low to high. The switch was doing what it was supposed to do.
off gnd, batt, open
low gnd, batt, gnd
high open, batt, gnd
I have not checked the squirters connector but will do so and report back. I have to paint my old unit and put it back in. When I do that, I'll test the squirters.