Ive fitted another time switch today and now the car starts and runs from cold without having to mess around.
I tested the yellow coolant sensor and its showing 15.3 M ohms, so its dead. Problem is, I substituted that sensor with a new one from a series 1 before and it still wouldnt run with the pressure actuator connected. Obviously the sensor wasn't fitted so it was only reading ambient temperature but the engine had only been running for 30 seconds or so before trying it anyway.
Is there anything else other than the coolant sensor that could cause it to shut down when the pressure actuator is connected?

Thanks