Hello all. I have a 2000 f150 4x4 4.6l with 155k on it. Runs like a champ. Ok the problem. My A/C and heater both work well. but the derection is the problem. When i turn either on it only comes out of the vent and floor. not a good direction when im tryin to cool or warm myself up.?? anybody know whats going on????? thanks for the info!!!!

 

You either have a vacuum problem or a bad heater control switch. There is a vacuum supply line that goes through the firewall near the battery. If there is no vacuum supply, the system will default to the defrost vents. Good luck!

 

sweet thanks again bro ill check it out and see if thats the problem.

 

Heater/ AC vacuum door air routing thru the duct

OFF
When OFF is selected:

--The A/C inlet duct door is at full vacuum, closing off outside air and admitting only recirculated air.
--The panel/defrost door is in the no vacuum position, closing the passage to the instrument panel A/C registers.
--The floor/panel door is at full vacuum, closing the passages to the panel/defrost outlets.
--The blower motor and the A/C compressor are off.

PANEL/FLOOR
When PANEL/FLOOR is selected:

-The air inlet duct door is at no vacuum, blocking the recirculated air passage and admitting outside air.
--The panel/defrost door is at full vacuum, closing off airflow to the windshield defroster hose nozzle.
--The floor/panel door is in the partial vacuum position, allowing airflow to both the heater outlet floor duct and the instrument panel A/C registers. There is also some airflow to the A/C side window demisters.
--The A/C compressor will be enabled when PANEL/FLOOR is selected.
--The blower motor is on.

FLOOR
When FLOOR is selected:

--The air inlet duct door is in the no vacuum position, blocking recirculated air and admitting outside air.
--The floor/panel door is in the full vacuum position, directing all airflow to the heater outlet floor duct.
--The temperature can be adjusted to mix airflowing through and around the heater core to achieve the desired temperature level.
--The panel/defrost door is in the no vacuum position, blocking air circulation to the instrument panel A/C registers.
--The A/C compressor will be disabled when FLOOR is selected.
--The blower motor is on.

FLOOR/DEFROST
When FLOOR/DEFROST is selected:

--The air inlet duct door is in the no vacuum position blocking recirculated air and admitting outside air.
--The panel/defrost door is in the no vacuum position directing airflow to the windshield defroster hose nozzle.
--The floor/panel door is in the partial vacuum position, allowing airflow to both the windshield defroster hose nozzle and the heater outlet floor duct. There is also some airflow to the A/C side window demisters.
--The A/C compressor will be enabled when FLOOR/DEFROST is selected to dehumidify the air and reduce windshield fogging.
--The blower motor is on.

DEFROST
When DEFROST is selected:

--The air inlet door is in the no vacuum position, admitting outside air.
--Both the panel/defrost door and the floor/panel door are in the no vacuum position so that most of the incoming air is directed to the windshield defroster hose nozzle. There is also airflow to the A/C side window demisters.
--The temperature setting will determine the amount of air that is directed through the heater core and the amount that bypasses the heater core.
--The A/C compressor will be enabled when DEFROST is selected to dehumidify the air and reduce windshield fogging.
--The blower motor is on.