Possibly a faulty thermoswitch, try unplugging it.
I think it's on the left side of the radiator as you look at the engine, in front of the power steering pump.( My vectra isn't here to check)
biffo
March 2009
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.