I turn my heater on;but I get no air flow threw vents.What is my problem. I can hear air flowing;but like I say no air come;s out of vents.

Item Part Number Description 1 18A318 Vacuum Control Motor-, Panel/Defrost Door 2 18A478 Panel/Defrost Door (Full Vacuum Position) 3 - Defrost Air Flow 4 - Side Window Demister Air Flow 5 18B545 Temperature Blend Door (Full Heat Position) 6 19860 A/C Evaporator Core 7 19A813 Air Inlet Duct Door (Full Vacuum Position) 8 - Outside Air Inlet 9 18A318 Vacuum Control Motor-, Air Inlet Duct Door 10 - Recirculated Air Inlet 11 18527 Blower Motor 12 19A566 A/C Vacuum Reservoir Tank and Bracket 13 - Vacuum from the Engine Intake Manifold 14 19B888 A/C-Heater Function Selector Switch 15 - Vacuum to the 4x4 Hub Solenoids 16 18495 Water Diverter Valve (Full Vacuum Position) 17 18476 Heater Core 18 18A559 Floor/Panel Door (Full Vacuum Position) 19 - Floor Air Flow 20 18A318 Vacuum Control Motor-, Floor/Panel Door 21 - Panel Vent Air Flow

Can you hear the blend door moving when you change the temp from cold to hot or vice versa? If not, then you need new blend door actuator. Also check the heater core for any blockage. (2 ways to tell....run the car til normal temp, and turn on the heat and feel the hoses by the firewall...if one is hotter than other, there is a blockage inside the heater core. Or disconnect both hoses at firewall, and put garden hose in one of those 2 open tubes and turn on the water...good flow or weak flow coming out of heater core tube? Weak flow means blockage) If there is a blockage, time to get new one.

It could be that; the FAN MOTOR works but the fan-wheel is not turning. This usually happens when the center spindle of the fan-wheel RUSTS and eventually loses contact with the actual wheel itself.

defrost is the defalt mode look for a damaged vacuum line going ti the control head

There are 3 likely possibilities:

1. Bad heater motor - a dead heater motor means no air flow
   
2. Disconnected or hole in air flow hose - sometimes a vent hose will dislodge just enough to disrupt air flow. Check underneath the inside of the passenger compartment for any loose hose connections. You can also turn the heat (or vent) on HI and check the air flow hose for any pinholes that also could disrupt your air flow
3. Bad Control Center - if the Control Center is bad, it won't trigger the heater motor to turn on and push air
   

you have a vacuum leak most likely inside the car if you can hear the hissing sound.check under the passenger side kick panel for the leak.

this sounds like one of your electrical door actuator modules is not working not letting air flow threw your heater core itself in the heater box assembly feel at the bottom of your heater box for a heat from the heater core if it is hot then the problem is misdirected airflow. If the door actuator works it might be the hand control that you

sounds like you need a new air distribution box, mor than likely a plastic link on the box is broken. Do you hear any motors trying to change the air flow?

For starters, do you hear the blower motor running when you turn the heat on? If it does blow is there any airflow coming from your air vents? If the blower motor runs and there is air flow from the vents there are a few other tiems to check. Veriiffy that the coolant is full, low coolant level will effect the flow of coolant to the heater core. If coolant is full you may have a clogged heater core, or one of the blend doors ( they regulate air flow between the A/C evaperator and your heater core) may be malfunctioning or the control head(temp control) is malfntioning.

the mix doors in the heater assembly arent opening and closing right