Blower will not turn off on 2003 Volvo S40

My air blower will not turn of when the car is on by simply turning the knobs to off. I can adjust the temperature but it runs on full blast the entire time the car is running. what is wrong and how can i fix it?

1 answer
There is a blower motor resistor under the climate fan box, next to the cabin filter, this is usually the problem part. The top Philips screw is the worst to remove off the resistor so have some patience and don't strip the head. Good luck -Sam