How do I replace the wiper assembly?

@mitchellmwbMitchell, If you still hear the rear wiper motor running when in the on position, it is possible the wiper arm nut has become loose. with wiper off, remove black plastic trim cap from wiper arm, loosen the nut that holds wiper arm on spline shaft, look at the splines on both the wiper arm and shaft for wear or damage, if look OK re position the wiper arm into normal stopped/park position and tighten and give it a try. If the wiper arm splines are stripped then replace the wiper arm, if stripped on the motor or if motor is no longer function, then the motor will have to be replaced. Links below may help. Good luck. I hope this helped you out, if so let me know by pressing the helpful button.

https://www.youtube.com/watch?v=RoRFxsnC...

http://www.toyotapartsdirect.ca/a/Toyota...

http://www.ebay.com/itm/Rear-Wiper-Arm-a...

http://www.autozone.com/electrical-and-l...