No vacuum at air con vent control knob in vu commodore

Theres a one way chec valve in the vacuum tubing thsts probly worn. A partstore can help u find it

Vents are vacuum operated. The vacuum line from the engine to the controller is broken some where. They usually break by the engine. Easy to repair. Some times the break in the harness. I just run a new hose to the controller. You may have to drill a hole in the firewall to get it there.

Turn setting for window demister off , air con comes on automatically on some vehicles when windscreen demister is on

clean out the drain under the windscreen and ensure that the drain hoses down inside the mudguards are not blocked . ON the dash controls close the vent to recirculate the cab air and not allow fresh air into the cab.

the actuator the changes the vent flap position is not working. Check vacuum hoses or module.

My 99 vt had a similar problem but mine was also leaking coolant inside the car.
Just to check it out you should remove the instrument facia, centre console and the side pannels that hide the vacuum pumps then you will be able to scope out exactly what is going on.
Be careful to not misplace any of the screws because the vt's make a hell of a rattle if there is anything slightly loose or missing.

WHAT ABOUT ANY FUSE OR RELAY FOR THE A/C ?

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.
--------------------------------
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.
   

EASY FIX HAD SAME PROBLEM WITH MY AUDI A4 2002 JUST LAST WEEK.....WILL BE ONE OF THE CONTROL MOTORS FOR AIR FLOW...UNSCREW THE 4 OR 5 SCREWS THAT HOLD THE GLOVEBOX IN PLACE TAKE CARE TO UNPLUG GLOVEBOX LIGHT WHEN LIFTING OUT...NOW YOU WILL SEE ALL THE CONTROL MOTORS RIGHT-HAND SIDE OF YOU...EACH ONE CHANGES THE AIR FLOW ...THE ONE FOR THE WINDSCREEN IS THE ONE NEAREST TO THE FRONT OF THE CAR..UNPLUG THE WIRING CONNECTOR UNDO THE 2 SCREWS NOTING HOW THE MOTOR SHAFT ENGAGES...EASY....IF YOUR UNSURE WHICH CONTROL MOTOR IT IS TURN ON YOUR BLOWERS AND TEST EACH ONE..SIDE VENTS, DEMISTER,ETC...TRY AND GET A SECONDHAND CONTROL MOTOR FROM SCRAP YARD...DEALERSHIP PRICES JUST A JOKE.. FOR A CHEAP TINY MOTOR NOT MUCH BIGGER THAN A MATCH BOX OVER A £100 SCRAP YARD £5 POUNDS...........HOPE THIS WILL BE OF SOME HELP TO YOU...

maybe a fuse problem but some of these problems are vacuum source problems also. if the vents are motorized, then it could be a fuse problem but if the vents are air solenoids, then it is a vacuum source problem.

you can verify this by looking underneath the globe compartment, if you can see the recycle vent controller, you can verify if the controller has electrical wires on it or just plain hoses.

if plain hoses you see, you could have a broken line from the engine vacuum to the controller.

check for broken small hoses from the controller switch going to the engine.

tnx 4 using fixya,

drcool