Has anyone ever had to replace the coolant sensor connector on a 1.9CDTI 8v? If so I'm just wondering where you sourced the connector from as I suspect that Vauxhall will want to sell me a new wiring loom.
On my car the connector's two wires move in and out ever so slightly - just enough to either break the connection or subject the connection to high resistance intermittently when the car is travelling >30mph. I've tried opening the connector up and packing it to help restrict the movement of the terminals, but the problem still shows intermittently, resulting in either a fault code or rogue readings on the temperature gauge (the thermostat was recently replaced with the revised version, which is when the sensor connection was disturbed and the problem started).
I am certain that the connector is the problem as I can replicate both faults (and see the wild temperature fluctuations in Op-Com) at standstill by wiggling the connector's wires. I don't suspect the new thermostat as the cabin heater temperature doesn't change when the temperature gauge's needle suddenly drops to the bottom of the scale.