My sons 2003 Highlander 6 cylinder suv A.C works but when the blower for heat is turned on there is no heat coming into the vehicle. Could this be thermostat problem, or heater fuse caused problem. The vehicle has been serviced by regularly by the dealership it was purchased from
Check the coolant level in the radiator (do this when the car is cold) If the level is low it won’t circulate to the heat ex-changer box under the dash. If the level is low you have to find out why and get that fixed.