lately i have been trying to use the heater in my car. and it only works on the defrost mode but just barly. i have no clue whaat it could be. it just warm air, and also on all the modes like feet or heat or even defrost it only comes out the passanger side and on the driver side its cold air. ive checked the inlet and outlet hoses and the're just nuke warm. not hot. any advice would be amazing. its freezing and i need the heat really bad. thanks guys.