open vents direct the air to come out them vents turn fan on,if feel air coming out even a motor nois is good,if flow is poor maybe pollen filter if fitted is blocked,, if blows cold air not hot when should could be no coolant in engin,if fan only works on 4 then its heater resistor,if motor not spinning pos fuse/switch,pull plug from motor wire a 12v bulb or use 12v test light(not led)turn fan switch threw 1-4 bulb should dim and brighten with difrent seting on switch,no then earth falt or switch,
steven,s
January 2012