After a bit of head scratching ive sussed this one even my local vauxhall dealer struggled. Ive got an Astra H elite with climate control and the fan wouldnt switch off just stayed on whatever speed you switched the engine off at. Take the glovebox out (4torx screws) look under the dash at the heater motor and to the right of this follow the 2 heavy cables from the blower itself to what is known as the climate control resistor. It is held in by 2 clips bit fiddly though. Part number is 90566802 bout 175 at vauxhalls or 60 quid on ebay. This unit has a constant battery supply and acts as a relay also hence the heavy wiring. The blower is fed this batt supply via the resistor. It is the earth that is variably controlled when signalled from the fan speed control knob. When faulty this unit continues to allow an earth even after ignition switch off. Hope this helps anyone with any model vauxhall with climate control. Im pleased to be helping as there were no solutions when I was stuck!
Disco Steve
October 2012
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