im sure the fan/ blower in my car has a mind of its own! do they usually speed up n slow down on there own?

Have you got the climate control? Mine (Octavia - but same unit?) does this all the time (even when not on auto) and it is fantasically infuriating.

im sure the fan/ blower in my car has a mind of its own! do they usually speed up n slow down on there own?

Is it generally when you select reverse gear ?

The system goes in to recirc mode when you select reverse so you dont suck exhaust gas in to the car.

im sure the fan/ blower in my car has a mind of its own! do they usually speed up n slow down on there own?

No - except recirc comes on in reverse as noted.

ha yes! it does! that what it is! im an instructor and today i was doing some bay parking an all i could hear was the bloody fan keep going mad, ill know in future cheers.