Making an assumption like that is why so many can't fix their own stuff. The assumption you just made is wrong, the pump working is not proof that the switch is OK.

With the wipers set for fast, and the engine idling, what is the voltage at the Body Control MOdule connector C3 pin 65?

Above 12 volts: Switch is OK.
Less than about a volt: Switch is the problem.

If the switch is OK, it can be the motor fuse (Fuse 20 in 2005s), the Body Control Module, the motor or the park switch in the motor.

Take a look in the wiring chapter of the service manual, the design is pretty simple.