I've run the little JCW wiper delay box in my old Landcruiser and know some folks with it in pickups. Works well and is probably easier to install than the factory parts. I think you need at least the relay and the wiper stalk, not sure if the wiring is present.

Wish it were as simple as it is to do on the olds VWs, just pull a jumper wire and insert the relay then pull the interlock pin in the wiper switch.