Hi TIm,
Usually when there is an issue with the park position it is the motor. Which would make sense that the wiper control failed, because it is probably drawing too many amps through the controller. Make sure to replace the fuse for the wipers with a breaker as stated on the product page for that part on our website.
We recommend adding the 15 amp Mini Auto Reset Circuit Breaker to go in place of the 25 amp fuse in position # 22 on your interior fuse panel. This way a amperage spike will trip the breaker instead of ruining the module.
Gary,
The reason Workhorse recommends replacing that fuse with that breaker is due to drawing more than 15 amps through the wiper module destroys them. The 15 amp breaker will open momentarily if the amp draw exceeds the 15 amps of current, which saves the wiper modules. You certainly do not have to use the breaker, but you may be replacing the wiper module again in the near future without it.