aircon blower speed going mental! e46 318

[ju6121]

the aircon blower speed has been going mental in my 318 lately. at times its fine then suddenly it starts blowing air at the highest speed regardless of what settings it on and i have to turn it off to avoid freezing. Any ideas what the problem is and possible costs involved?

[blackspider]

Sounds like the heater resistor pack has failed...most common cause.
30 mins to replace and about £50 for the part