Cool!
The washer bottle lives inside the wheel arch, behind the wheel arch liner.
You have to disconnect the undertray piece underneath the radiator from the wheel arch liner (it drops down, so you only have to take off the bolt connecting it to the wheel arch) and then undo the 2 or 3 screws holding the liner in place. It drops straight down.
The waher bottle is clamped to the inner arch and the motors and pipes are pressed into it (rubber seals). The pipes are rubber and can perish.. but because they're rubber sometimes they leak and other times they don't.
If your motors don't work, you have to go hunting for second-hand ones as they are not generally available separately from Fiat (need the whole wash bottle) but some after-market ones apparently exist.
The tube coming out of the motor goes directlt to the valve you highlighted.. so not much to check. If water comes out of the motor but doesn't reach the valve, take the tube off and check if it's blocked. A new one will be about £1 though (and is plastic now).
Ralf S.