Demister wont turn off

[vtgen3]

My vt commodore wont switch off from the demister. the control knob will rotate and ive pulled the dash out to make sure its all connected, which it seems to be, but everytime u turn the fan on the demister comes on only.

also had the air con regassed about 6 months ago and when the problem first started with the demister, the air con would actually come through the demister vents but now the air con wont engage at all.

ive heard there is a electric module that can fail which may be the cause, does anyone have any ideas what it could be and how i can go about fixing it without sending it to the air con guys?

any help would be appriectiated!

cheers
Nikki

[accentstencil]

First check the thin vacuum hose connected at the rear of the intake manifold. It sometimes comes off, giving you no vacuum to change vent positions.

[vtgen3]

thanks for that tip! ill give it a go tonight and see what happens

[utekid2]

the same thing is happening with my VT i dont have a clue wat to do? air con and heater work but its just the postions (head feet window) stuck on window, knob turns freely. do i do the same thing?? and where do i check and what am i looking 4? i know nothink bout cars but i can follow instructions. please help its geting hot up here northern SA

[accentstencil]

the same thing is happening with my VT i dont have a clue wat to do? air con and heater work but its just the postions (head feet window) stuck on window, knob turns freely. do i do the same thing?? and where do i check and what am i looking 4? i know nothink bout cars but i can follow instructions. please help its geting hot up here northern SA

Here is a link to a thread in which I posted a photo of where to look.
Air flow direction changer problem
Check that the thin hose is connected and in good condition. This may not be your problem but it often is.

[utekid2]

thanks accentstencil ill try that wen it cools down in the shed, also in that thread they talk about behind the facia how do i pull that apart if i still have no luck? its not like me old EB falcon undo screws and waalaa.

[accentstencil]

thanks accentstencil ill try that wen it cools down in the shed, also in that thread they talk about behind the facia how do i pull that apart if i still have no luck? its not like me old EB falcon undo screws and waalaa.

This link might help: Blue LED Dash Conversion

[utekid2]

thanks heaps accentstencil at least those posts have a few pictures awesome. i checked my vac hose behine intake and it was split but i cut the split out and joined up as normal it works, the only problem is that cant change air flow direction to quick otherwise it goes straight back to window setting. but thanks for the help atlest some people are out there to help not just sit back on there arse and look at these lol thanks again

[utekid2]

MORE HELP PLEASE
it was working fine yesterday and tis morning but now its gone back to normal (window) vac hose is on (will a little hose clamp on it help? ) when i turn the direction change knob around i can hear a vac noise or air whatever? what this mean?

does this mean i have to take dash apart to look behind air con dials to make sure vac lines are conected???? can anyone show me a link how to do from start to finish! ive looked at the post that accentstencil gave me and it shows a bit how to do a bit (more then i knew)

[accentstencil]

MORE HELP PLEASE
it was working fine yesterday and tis morning but now its gone back to normal (window) vac hose is on (will a little hose clamp on it help? ) when i turn the direction change knob around i can hear a vac noise or air whatever? what this mean?

does this mean i have to take dash apart to look behind air con dials to make sure vac lines are conected???? can anyone show me a link how to do from start to finish! ive looked at the post that accentstencil gave me and it shows a bit how to do a bit (more then i knew)

I would check the rest of the hose that you reconnected, it might need to be replaced. Also check the valve that is on that hose, you should be able to to suck air through in one direction and not be able to blow through in the other direction.

[utekid2]

yeah ive sucked throu one way valve it works suck dnt blow back thro. all the rest of hose seems in tacked how do i test if it leaking(squirt with windex, water)
when i change the postions in car it sounds like the sucking vac noise is coming from inside behind dials but i cud just be hearing things?

[accentstencil]

It is normal to hear a hiss when changing vent positions.

[utekid2]

ok i took dash apart and found the little silcone plug which all the vac lines run to. the main vac line from intake(black) the plug side was damaged so instead of vacing thro system it was sorta bridging to the line next to it, hence there was no vac in the system to open different flap doors. thanks for all ya help accentstencil without ur help i still be lookin under the bonnet n still thinking of how to rip dash apart.
i have ordered the part its called the VAC HARNESS part no 92140716. $32 odd dollars for the whole lot of vac lines( 5 ) now ive gota find where they all go.
this mite help someone in the future

[accentstencil]

Glad you finally found the problem.

[etch289]

VR DASH DEMISTER SWITCH LIGHT STAYS ON
the switch itself seems to work ok

when u press it in & out it it does as it should
but the orange light stays on

any ideas out there as to wat maybe happening wrong?
thanx

[stevoss]

this thread is probably one of the best so far. had the same problem although with climate control, found even with the ac on it would only blow fresh air, demist and heater on at the same time, so i started reading through the gregory's manual i had and after 2 hours found out that is what happens when you dont get a vacuum supply to the system, so i started checking starting at the rear of the manifold in the engine and disconnecting the vac line, checking to make sure it wasnt blocked then the little valve i pulled it off and blew through it to make sure it would only go into the engine way and not the other(failing that its a $16 part from holden) then disconnected at the vacuum canistor under the passenger side foot well, with 2 black vac lines going into the side of it(pulled each off 1 by 1 to make sure it was actually getting the vac signal), then played with the solenoid control box, after all that it seems to have dislodged or fixed the issue so happy me