Air flow control for demister is stuck.

I'm guessing that no air blows out of the upper vents when you select the demist setting? There are numerous flaps in the air conditioning systems on automobiles that move to control where air flows. Chances are one of those has either failed or the actuator has broken. Depending on your level of skill you may be able to rig the doors into the correct position without removing the dash. A complete repair will probably involve removing the dashboard and replacing the failed component.

Not sure what car / truck but most have a nob on the dash with little pictures of the things that will have warm / cool air blown, so you need to select the right picture, alternativly turn the nob all the way to the right and see what happens then all the way to the left, you should find the air comes out of the demist vents in one or the other. Hope this helps

Sounds like the switch nob itself is wore out. you may need to replace that assembly, not just the nob but that cluster that has the nobbs on it. good luck

check under the hood near firewall for a broken plastic skinny vacuum line.

blend door motor bad or door broke

When the engine is cold,check the coolant level.

Make sure it's on max.

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A coolant system should be flush every two years.

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If you did a coolant flush recently then air pocket can be the cause of the un-even heating problem.

The DIY method is to drive you car onto a ramp or a steep hill.

Iet the engine cool off and top off the coolant tank.

Set MAX heat + MAX fan

Let the engine ran for 20 minutes wih the cap off and the trap air will escape from the coolant reserve tank,

Check coolant level and top off coolant when the engine cools down.



A shop will charge $75+ for this but using an air operated excavate tool!

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A car with over 90K miles may experience linkage problem to the heater control valve.

The heater control valve (near the firewall) may be stick over time.

Open the hood and move the heater to max and min. Back and forth.

Clean and lube the linkage with WD-40 to free the heater control valve.

If it's a vacuum type heater control valve then cash for leaky vac. hoses.


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Move the fan switch back and forth to re-new the electrical conductors.

Pass a vacuum over the control panel to prevent dust build up behind the console.

something might be stuck in the ducting not allowing the door to move and direct air flow to the other ducts. First pull straight on the nob and pull it off of the dash. then take a pair of pliers and make sure the smell metal peg will rotate.

may be just a cable adjustment.


SECTION 412-01: Air Distribution and Filtering 2001 Focus Workshop Manual DESCRIPTION AND OPERATION Air Distribution and Filtering The new heating and ventilation system ensures even air distribution.
The temperature control and air distribution flaps are controlled by two operating cables. All vehicles have a recirculated air function, with the flap controlled by a servo motor.
Air is supplied to the windscreen and side windows regardless of the air distribution setting.
The clean air filter is fitted as standard in most countries. This cleans the incoming fresh air of pollen and dirt particles. It must be renewed after every 40,000 km under normal operation conditions, or after 20,000 km under difficult conditions. If no clean air filter is installed, a plastic grille is fitted over the air intake. This can easily be replaced with a clean air filter.
Air distribution operating switch
Face level The main flow of air enters the passenger compartment at face level.
Face level/floor level The main flow of air enters the passenger compartment in equal parts at face level and floor level, and a small amount flows to the demister nozzles of the side windows.
Floor level The main flow of air enters the passenger compartment at floor level, and a smaller amount flows to the demister nozzles of the side windows.
Demist/floor level The main flow of air enters the passenger compartment in equal parts at the windscreen and at floor level, and a smaller amount flows to the demister nozzles of the side windows.
Demist The main flow of air enters the passenger compartment at the windscreen and a smaller amount flows to the demister nozzles of the side windows.
Air distribution operating switch Air distribution operating cables
NOTE: The Bowden cables for LHD and RHD vehicles are identical. However, they are fastened to the air flap operating mechanism with the respective reverse side of their connectors.
The air distribution switch operates with two Bowden cables. The cables operate the air distribution valves in the heater housing.
To remove and install the cables, the rotary switch must be turned as far as it will go to the left. The air flap mechanism engages easily in this position, making the installation of the cables easier.
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Air Distribution Cable Control Assembly Removal
CAUTION: Disconnect the battery ground cable. For additional information, refer to Section 414-01 .

1. Remove the radio/cassette unit and the CD player (if equipped). For additional information, refer to Section 415-01 .

1. Remove the bezel with heater/air conditioning controls.

1. Remove the bezel with heater/air conditioning controls (continued).
   • Pull off seven electrical connectors (six shown).

1. NOTE: To remove the Bowden cables, turn the rotary switches as far as they will go to the left.
   Remove the bezel with heater/air conditioning controls (continued).
   • Unclip the Bowden cables.

1. Remove the lower driver's side footwell trim.

1. Unclip and remove the air distribution Bowden cables.

1. Unclip and remove the temperature control Bowden cables.
   • Unclip and remove the temperature control Bowden cables.

Installation

1. NOTE: Route the new Bowden cables without kinks and check for easy accessibility.
   NOTE: To install the Bowden cables, turn the rotary switches as far as they will go to the left. The mechanism engages easily in this position.
   NOTE: The Bowden cables are identical for RHD and LHD vehicles, although they are fastened to the air flap operating mechanism with the reverse side of their connectors.
   Install the components in reverse order.

1. Check operation of the Bowden cables.
   

When you set the Defrost does any air flow from other ports?