Air con vacuum issues

[Matthew Moore]

Hey lads, have issue with VZ air con. Under load the air vents change and blow directly onto windscreen. Am changing the vent actuator at the moment (pink and orange vac lines).
Could it be anything else if this does not fix the issue?

Any assistance would be great. Cheers
Matt

 

[Bardy-II]

Vacuum hose on the back of the motor on the drivers side, has a white cylinder (check valve) on it.