Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
Your Astra could have one of many problems.
Can you tell me whether there is a module mounted behind the LH foglight? If there is, it is the cooling module.
There could be a wiring fault.
You could have a bad thermostat or water pump.
The coolant temp data appears in the ECM data and the cooling module data.
If they conflict each other, the light comes on.
Hope this is of some help.