1997 Chrysler Town & Country Question: No Heat,tryed everything

NO heat, I have replaced therostat,water pump,rad.,had comp. check on dash buttons
for doors binding,checked houses at heater core they are very hot, at idle luke warm,driving nothing,have contols for driver and pass. and rear heater
also checked for air lock,a/c works great in hot summer heat,Im lost on what to do next
has 130,000 on van,never used heat untill coming to M.N.,had car in Florida