Air conditioning ECU fault

[jay8086]

I've got a fault shown by Peugeot Planet that i'm having trouble tracing. After doing a global ECU scan it sometimes reads the air con ecu sometimes doesn't. When it does read the ecu it usually states 'Permanent Fault. Coolant temperature sensor. Open circuit or short circuit to +ve.' I've replaced the green and the brown coolant sensors even though the old ones tested ok, i've checked the loom for continuity between the brown sensor and the connector down by the rad and the continuity is good with no shorts. Even when pug planet shows 'no fault present' when you go to 'after repair select this' then 'clear faults' it states 'fault(s) present'.
I don't know what to test or replace next. Anyone got any ideas?

[jay8086]

Has anyone got any ideas on what this fault could be? I've even replaced the twin fans now and it still rarely reads the aircon ecu, whether or not the cars running or the ac is turned on. When it reads it still shows the coolant sensor fault despite it being replaced and the old one tested ok, wiring checked as above and i'm completely out of ideas on what to test next.