t4 water sensors

[DVR68U]

hey guys im having trouble starting and running my van atm 2lt petrol. i was wondering if somebody could give me info on which sensors do what on the water outlet on the head. the 2pin 4pin and the one underneath that is a 4pin aswell i think. but the one underneath doesnt have anything connected to it and there is no wires that i can find that plug into it.
any help would be great
cheers brenton

[Jmac]

Mate the one causing the ecu to be fuzzed is the BLUE sensor. Replace the seal too its peanuts and well worth it. They are very common to cause bad starts. Injection pulse length is incorrect. Some were so bad they would not start at all over a simple little switch.
Good luck