....i think the pins are to blame as there not 100% fixed to the pcb i think moisture can get in as there was a little rust in mine (i forgot to take a pic yesterday but have done now) they must be a very slight vibration from the engine and after 10 years was worn some of the contacts away some solder could do wonders i suppose....
I'm a bit confused here, what pins are you talking about? the pins I'm on about are inside the
, the top 3 rows of pins in the picture below
The rust you can see on your attached pictures is nothing that would stop anything working, it's just the metal on the ends of the solenoids that has a bit of surface rust. The
isn't sealed to the valve block so moisture / water can get in between the two, hence the rust you can see on yours.
Water can't get inside the
as it's sealed, the solenoids are mounted on silicone to cushion them, this silicone also seals the pins from the solenoids to the circuit board, in fact you can see where the silicone has came through the pin connection holes at the bottom Left in the picture below.