heater & fan does work intermitently,too cold here in Alaska.what would be ?

You need a blower motor

could be a blower motor or the resistor

That would be if the heater has gone bad, and you will have to take your car to the dealer and have them look into the heater system and defroster system. If it all needs to be replaced it can run you between $200-$1,000 depending on what they do to replace the heating system. I would not jiggle with the control knobs at all, because that will only make the matter worse. So you are better off to take it to the dealer.