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[GrahamM663]

I have noticed a problem this morning with the ventilation system.

The car is a 94 2.5 v6 with the standard heating controls.

When rotating the selector from dash vents through to the screen the air is always blowing out the dash vents.

If I feel for air at the foot well or screen it is there when it's supposed to be. But it's always there at the dash vents.

Any ideas where to start?

Thanks

[Doctor Gollum]

Are the various flaps cable controlled on that

Accessing the various levers and flaps and fix whatever is broken. But don't force anything that is stuck otherwise you'll break it.

Stuck flaps can be freed by splitting the heater box. As is a proper repair of anything broken. But as that's a dash out job, people will tell you to scrap it or live with it. Why they have that attitude is beyond me, after all it is only held in with nuts and bolts. 

[GrahamM663]

The heater controls are cables, both passenger and drivers side works fine.

The screen, lower and recirculation are vacuum controlled and all blow air when you rotate the knob to the correct location.

My issue is the dash vents blow in every position. And they shouldn't.

I have removed the control panel but I cannot see what switches the dash vents on and off.

Thanks

Are the various flaps cable controlled on that

Accessing the various levers and flaps and fix whatever is broken. But don't force anything that is stuck otherwise you'll break it.

Stuck flaps can be freed by splitting the heater box. As is a proper repair of anything broken. But as that's a dash out job, people will tell you to scrap it or live with it. Why they have that attitude is beyond me, after all it is only held in with nuts and bolts. 

[Doctor Gollum]

Check for a vacuum at the heater control panel.

[GrahamM663]

I have,  vacuum doesn't control the dash vents. The vacuum is there and operates the lower vents, upper vents and recirculation.

The Haynes shows you these and the correct colour piped that feed each. All checked and working.

The Haynes doesn't tell me what controls the dash vents but I can see that they don't have their own vacuum feed. So what controls them?

Thanks

Check for a vacuum at the heater control panel.

[TheBoy]

I seem to recall 2 variants of the manual heating controls, but I think the main difference was around fan speeds.

But either way, the direction control knob controls the air flow to feet, dash vents and screen, so it must be something from there.  And from what I remember with the only Omega I ever (and briefly) had that had manual controls, its just vac pipes.

Recirc is a different button on the row of buttons underneath, as far as I can remember?

[GrahamM663]

Recirculation is controlled by vacuum as well.

Now I have the selector out I cannot figure out how the dash vents actually close off. There is a vacuum line for the lower. Upper and recirculation. So I'm stumped unless I take out the entire air box.

I seem to recall 2 variants of the manual heating controls, but I think the main difference was around fan speeds.

But either way, the direction control knob controls the air flow to feet, dash vents and screen, so it must be something from there.  And from what I remember with the only Omega I ever (and briefly) had that had manual controls, its just vac pipes.

Recirc is a different button on the row of buttons underneath, as far as I can remember?

[cam.in.head]

silly statement probably because i havnt had an early omega but are the centre vents actually  controlled at all ?  reason im saying is that many 80's vauxhalls had heating controls for cabin and demist as you would expect but centre dash vents were always live.just opened and closed as you need them by hand .?

[GrahamM663]

It's all the dash vents and not just the centre. But I know what you mean.

Thanks

silly statement probably because i havnt had an early omega but are the centre vents actually  controlled at all ?  reason im saying is that many 80's vauxhalls had heating controls for cabin and demist as you would expect but centre dash vents were always live.just opened and closed as you need them by hand .?

[TheBoy]

silly statement probably because i havnt had an early omega but are the centre vents actually  controlled at all ?  reason im saying is that many 80's vauxhalls had heating controls for cabin and demist as you would expect but centre dash vents were always live.just opened and closed as you need them by hand .?

The fact they (from memory) have airflow settings for feet, face and screen would lead me to think they can be controlled from the centre controls, as well as from each face vent.

[TheBoy]

So, I was intrigued enough to look at TIS.  Its not been fired up in years, and predictably the battery was as flat as a witches tit.  But now it has enough power to boot up....

The actual text says:

The air distribution control knob opens and closes the defrosting valves and the footwell valves by vacuum pressure.


Which implies the face vents aren't controlled in any way (other than by opening/closing each face vent).

[GrahamM663]

My first pre face-lift definitely didn't do this.

Thanks


 

So, I was intrigued enough to look at TIS.  Its not been fired up in years, and predictably the battery was as flat as a witches tit.  But now it has enough power to boot up....

The actual text says:

The air distribution control knob opens and closes the defrosting valves and the footwell valves by vacuum pressure.


Which implies the face vents aren't controlled in any way (other than by opening/closing each face vent).

[MonzaGSE]

As mentioned there is 2 different manual heater systems in the Omega. We have 3 pfl Omegas. All with manual controls. The 1994 and 1995 Omegas have 4 speed fan and dash centre and side vents live at all time. The 1997 Omega has 5 speed fan. And all the dash vents controlled by the heater control. Also the placement of the symbols at the air direction knob is different. The older system has screen all the way to the left on the knob while the newer had front screen straight up on the knob. Personally i much prefer the older system in the winter in Norway. I put it in front screen/footwell mode and it will also blow out the side vents to keep the side windows ice/fog free. With the newer system in the 1997 i find i sometimes have to alternate the selector back and forth to keep both the windscreen and side windows clear. Because that dont blow out the side vents unless selected.

[GrahamM663]

Thanks for the advise but with a borescope I can see there is an issue inside the heater box. So it will be coming out.

As mentioned there is 2 different manual heater systems in the Omega. We have 3 pfl Omegas. All with manual controls. The 1994 and 1995 Omegas have 4 speed fan and dash centre and side vents live at all time. The 1997 Omega has 5 speed fan. And all the dash vents controlled by the heater control. Also the placement of the symbols at the air direction knob is different. The older system has screen all the way to the left on the knob while the newer had front screen straight up on the knob. Personally i much prefer the older system in the winter in Norway. I put it in front screen/footwell mode and it will also blow out the side vents to keep the side windows ice/fog free. With the newer system in the 1997 i find i sometimes have to alternate the selector back and forth to keep both the windscreen and side windows clear. Because that dont blow out the side vents unless selected.

[MikeV6]

Did you get this sorted in the end Graham ?