More then likely the solenoid has gone bad
What were your steps that you took for you to determine that the 2 wires at the valve were good?
An ohm reading with a multimeter would tell you if the solenoid is shot or not.
If you don't have a meter you could pull the single wire ( Not the common that's hooked up to everything else) and connect that wire to another valve in the box. Then turn on zone 3 and see if that other zone kicks on. This would tell you the valve in question's solenoid is more then likely bad.