Heat not working on 2000 Ford Taurus?

about two months ago, i had the water pump on my car replaced and a coolant flush after it dumped all the antifreeze on my parking lot and after 3 months of only having intermittent heat in a car that used to get stifling hot. i read somewhere that if they also do not flush the heater core, "spines" for... show more about two months ago, i had the water pump on my car replaced and a coolant flush after it dumped all the antifreeze on my parking lot and after 3 months of only having intermittent heat in a car that used to get stifling hot. i read somewhere that if they also do not flush the heater core, "spines" for lack of a better term- that broke off the old pump can travel and get clogged in the lines and/or the heater core. anyway, my problem is that the only way i could get any heat was to run the defroster, and after about 15 minutes my car would be warm enough so that my fingers werent frozen solid. if i was making a long trip, my car would eventually be able to provide heat with the heat functions. my step mom has the same issue in her exact make and model that i have and living in wisconsin, its no surprise that it takes forever for the car to warm enough to provide heat. the fans would still blow. after a while, i started to hear a clicking noise coming from inside my dashboard, behind the radio and glove box when i would turn the dials. well, eventually something had to give, because now nothing blows out, not even the defrost. turn everything on, and all i get is clunking/clicking.
could this still be a fuse? do i just need a heater core flush? should i replace the heater core? the blend door? the resistor? my dad will be able to do the labor, but im curious where to begin so i know what parts to pick up.
any advice?
6 answers 6