Air Conditioner an Vacum problem

[johnmic]

I have a VT Berlina with climate control, the air conditioner works great and blows out cold air, the problem is whilst driving under normal load conditions I can change the air to come face vents,, to floor to windscreen, but if I accelerate when the a/c is blowing out the face or floor vents it changes to blow over the windscreen and stays there till I stop accerlating and again drive maintaining a constant speed.

Any help would be great.:

[Fletch_QLD]

This is a common problem. It is the solenoid actuator - it cannot be serviced/repaired - it needs to be replaced - it is unique to the climate controlled variants, but I think it is the same from VS through VY. From memory it's like $120 new or around $40 on ebay 2nd hand (take your chances).

On the VS it is located underneath the stereo and is a little tricky to access (about as tricky as removing the stereo) but is a simple matter to replace once you access it.
On the VY it is easier to access - passenger side kick panel of center console.
On the VT it is attached to the blower housing ...

[Rhin0o8]

On The VT you will see it once the Glovebox is removed.

It also may be a leak in the Vacuum tank.
I would suggest that by the symptoms you have described

"I accelerate when the a/c is blowing out the face or floor vents it changes to blow over the windscreen and stays there till I stop accerlating and again drive maintaining a constant speed."

[johnmic]

Many thanks everyone for all your help, I greatly appriciate it. Cheers

[lufkin]

also check the 1 way stop valve on back of manifold behind plenum

[Harpo]

I dont think that the solenoid valve is the answer. Its happened to me twice. The 1st time it was a faulty vacuum actuator (the rubber seal tore) and the second time it was as Lufkin described, the "check" valve which was just a bit loose on the tube. But there is some good info in Fletch's tech sheet. You can check the solenoids with a multimeter (each coil should read about 90 ohms resistance) and you can hear if the vacuum tank is leaking. To test the check valve, unplug it from the vacuum tank (remove the larger hose, it goes straight to the manifold which is the sourse of the vacuum) then with the motor running, stick your finger over the end of the hose, it will stick to your finger with suction, wait a few seconds then, with your finger still over the hose turn the motor OFF. If the valve is OK the hose will remain stuck to your finger until you release it, if it drops off after a few seconds .....its the valve.
Have fun
HARPO