Air con whistle? Vy II S one tonner

[Doom vy tonner]

Hi guys. When I'm driving there is a whistle coming from under the dash. The more the engine revs the louder it gets. I've been told by a mate it's probably the air con. Just wanted some ideas on what you think and how I might fix it? Cheers

[CAPRILICIOUS WL]

You more than Likly have a vacuum leak.
One of the vacuum hoses has come of.

Does your ac and heater function normal in every mode as in face foot window etc?

There are hoses under your head unit u have to pull the panels on both sides of the headunit to get to the "mode actuator"
There should be to either white or black ones each having two hoses.
These are pics of mine.
Make sure that all the hoses are plugged in.





There are also other vacuum lines underneath the glove box.

Hope I've helped
Cheers
Dave.