The heat don't get hot but blower works
Check coolant level. Does engine appear to work within operating temperatures? If not check thermostat. Check the heater lines to the heater core, they are about 1" diameter, and run from the back of the engine (usually) to the firewall. They should feel pressurized and hot to the touch (as hot as the radiator hoses). If not you may have an obstruction or blockage in the heater core. Check if the temperature blend door is working. Do you have cold AC? Does it switch between hot and cold from the temperature select switch? If not the blend door may be stuck in a closed position, preventing air from passing over the heater core. If everything points to the heater core as deficient, try doing a flush on it. If you have done any recent radiator/hoses servicing, make sure all the air is out of the system, burping the air out.