Climate control issues in VY Calais

[Rychous]

When I have the aircon on, it sometimes goes from the cabin to the demister without me doing anything. Apparently this is a factory thing? Can I shut the darn thing off, it seems to be so random but its shitting me to tears!

[H Bomb]

Yep, mine has the exact same problem, has always done it. The 'dealer" said it was a design thing, but there is a few other posts on here that say otherwise, there is a few things it could be apparantly, I have tried 2 of them and now only have the "actuator" to replace up in the dash, cant be bothered to do it so haven't tried it yet. Search for climate control issues and you will find heaps of posts on it.

[Fletch_QLD]

99.9% of the time on all models from the VS through the VY with climate control it'll be the solenoid actuator.

On the VY it's located kind of under the stereo - but on the passenger side. Pretty easy to get at, just remove passengers rhs kick panel and there it is.

$120 from your local holden dealer or around $40 second hand (ebay/wreckers) - problem solved

[Surfwagon]

As said above it is usually the actuator and happens when the vacumm changes like when going up hill under load or when accelerating.
You can always turn of the AC by just hitting the AC button or just go to manual AC mode although this doesn't always stop it from changing direction.