Maybe try cleaning the solenoids first. If your lucky and have jar-tops then just unscrew and clean and replace. Sometimes dirt or junk in the water can stick these in a certain position. If the heads arent popping up at all then you prob dont have any pressure in that zone. Since I assume 3 is fed by the same supply as 1+2, you might have bad solenoids. First try cleaning them. They have small plastic diaphrams that can get clogged by pinhead sized pieces of dirt. If that doesnt help try replacing one. For the jar tops, you just need to replace the top. Im preatty sure there isnt anything impacted in the bottom part. But i havent hd to fix one yet this year so im a little foggy.