I just bought a 99 F350. The guy I bought it from said the a/c doesn't work because the pump is froze up so don't turn the a/c on or it will fry the belt. I went to pick the truck up yesterday and he said don't turn the heat on or it will fry the belt. I asked him several times to make sure he said not to turn the heat on or the belt would fry... Does anyone have any insight on this? Thanks.