The rear heating and AC vents on the roof are not blowing air. The return works but the upper middle and rear seat vents no longer work.

Marvin

• 85242 Answers
• Posted on Nov 24, 2008

SOURCE: Heat/AC blower not blowing air

heck the blower fan speed control resistor, it is located near the blower motor, they are cheap to replace and the most common cause of this issue

SOURCE: 2004 Pontiac Montana blows cold air in defrost

There is a mix damper inside your duct that controls the heat over heater core and ac evaporator that to your floor and one to your defrost. it is probable an electric actuator, that is not functioning properly. If yu can locate it and manually move it, you might have to remove the actuator motor first, you should be able to figure out your problem, I hope this helps! merry Christmas!

SOURCE: 03 chevy tahoe

There are seperate blowers for the front and rear air. It is most likely either your blower motor or the resistor, both located under the passenger side dash. I got a blower from a salvage yard for $25, But ended up having to get the resister from the dealership for about $130. Hope this helps.

SOURCE: 2004 Ford Expedition rear floor cool/heat

Item Part Number Description 1 — Air inlet door 2 — Temperature blend door 3 — Headliner airflow 4 — Auxiliary mode door 5 — Floor airflow 6 18476 Heater core 7 19860 Evaporator core 8 19805 Blower motor
The auxiliary A/C and heating system has the following features:

• The auxiliary A/C and heating system is functional whenever the instrument panel mounted A/C control is in any position except OFF.
• The auxiliary blower motor recirculates the air inside the vehicle. Outside air is not available to the auxiliary system.
• Air is cooled and dehumidified by the auxiliary A/C evaporator core only if the instrument panel mounted A/C control is adjusted to a position that requires A/C compressor operation.
• The temperature blend door and the auxiliary mode door are controlled by electric actuator motors.
• Movement of the auxiliary temperature control between COOL and WARM causes a corresponding movement of the temperature blend door to mix air flowing through and around the auxiliary heater core.
• Movement of the auxiliary mode control between PANEL and FLOOR causes a corresponding movement of the auxiliary mode door to direct air flow between the panel (headliner) registers and the floor duct.

1. Remove the RH quarter trim panel cup holder and access panel.

1. Remove the screws.

1. Disconnect the blend door actuator electrical connector.

1. To install, reverse the removal procedure.

SOURCE: ac vent problem

Damper/flap for driver's side is probably stuck. Try moving the selector from cold to hot several times. Also, move the recirc/outside air control if the previous doesn't work.