It is very rare that the heater blower switches go, try taking the blower motor out, easy job.. 1 .. try & turn the inside of the blower by hand, if it moves by hand freely, then suspect the blower motor to be faulty... if not moving it will just need a little oil on the end bearing, then gently prise it to move... 2 .. take the cover off (under the bonnet), there are clips on each corner, you will need a long then flat screwdriver, unclip the rear 1st .. 3 .. then there is 2 phillips screws, one each side of the motor, undo them & lift the motor assembly out..