A/C & Heater Modes Control

[jaisvz]

I have a strange problem with my air con / heater mode dial in my sv6.
When i try and change it, it always stays on windshield mode no matter where i put the dial.

Now, i plumbed a boost gauge into the small 4mm hose off the back of the manifold that i believe supplies the vacuum for these controls. Still worked fine after this.

Then my blow off valve was plumbed off this same hose. Now it does not work!

Re plumbed my blow offs else where, still doesn't work.

Re plumbed boost gauge else where, still doesn't work.

If any way can, please take a photo off the back of there manifold where the brake booster is connected and the little hose is next to that. I just want to see what it looks like originally.

Thanks

[jaisvz]

bump,
Anyone have any ideas for this?
I have just ripped apart my whole dash trying to find the problem, cannot find anything apparent.
Vacuum hose seems complete and un-kinked, one way valve installed in right direction and functioning.
Switch seems to be getting power. Is there a relay for the valve to change the air direction?

I am getting very frustrated with this.

Jai

[Danoz]

The turbo is applying positive pressure to the plenum. The A/C controls work on vacuum. You eliminate/weakened this when you added a turbo. Thats my theory.

[andyman]

at idle when you remove a vacuum hose, is there any vacuum? or is there a small amount of boost or is the pressure almost equal?

if vacuum is a problem, you may need to source an aftermarket vacuum pump.. i take you have a turbo setup?