The spray head will normally be in the bay on the passenger side where the gravity water fill is located. The panel can be taken off by removing four screws on each side. The side where the compartment door is located is easy. The other side requires a thin Phillips screwdriver and put masking tape over the edges of the compartment to prevent scratching the paint. The door is not heavy, just bulky so best done with two people. Inside you will see where the hose goes into the tank. Remove the sprayer from the tank and drill the holes out slightly larger. Stopping up is the result of "crud" drying inside the spray holes so it's best to use the sprayer almost every time you dump even if just for a few seconds. The spray head will look similar to below.
2017 Phaeton 40IH XSH Maroon Coral - Power Glide Chassis with IFS
Previously '15 Tiffin Allegro RED 38QRA and '06 Itasca Sunrise 35A
'16 Jeep JKU Wrangler Sahara or '08 Honda Goldwing