Ventilation buttons inoperable!

May 24th, 2006, 13:49

Hello!

Just had my 240 in for service, and the ventilation buttons, which were just fine before she went in, are now not directing air to the windscreen, floor etc. Rather air is just coming out the face vents.

Is this maybe a fuse issue, or has something been 'bumped' during the service?

Cheers!

morsing · May 24th, 2006, 14:54

Buttons? Do you mean the sliders? Or the things on the vents themselves?

Alec Dawe · May 24th, 2006, 14:56

Vent Buttons?????
Oh I see you're in Australia, so I suspect that you've got a different arrangement for heating and ventilation.

Hmmm, not seen any 240 with button control all rotary knobs and slides here

Alec Dawe · May 24th, 2006, 15:06

AH!!! Just looked in the Haynes manual, and found an American spec picture with one rotary knob, one slider, and three push buttons for air direction, so I suspect that yours is the same.
Looking at the picture, it seems that the air flow is operated by the push buttons, which are powered from a vacuum tank which seems to be located behind the push button panel somewhere, (looks like 4 tennis ball sizes balls joined together in a row!), taking its supply from somewhere on the inlet manifold, (pic is not very clear). The vacuum pipes then go to vacuum operated diaphragm actuators on the air supply trunkings.
I would suspect then that either a mechanic has knocked off the vacuum hose from the engine somewhere, or that one of the hoses is kinked/blocked, or holed in some way.
The drawing also shown a non-return valve in the system, just behind the push button panel in the centre consol. That might have become deranged or blocked.
Looking at the drawing, the push buttons are all vacuum, no electrics involved (apart from the obvious like the fan motor etc) so I doubt its a fuse if you've got air coming from some of the vents.
Have a scout round for loose pipes, holes, blockages etc.

May 24th, 2006, 22:56

Thanks for that! I didn't know we were special down here and that everyone else was having to make do with sliders!

morsing · May 25th, 2006, 10:09

It's because you have the A/C system. The vents are vacuum controlled because it has to open different ones automatically for the A/C ventilation I believe.

May 24th, 2006, 13:49	#1
roverlei Guest Location:	Ventilation buttons inoperable! Hello! Just had my 240 in for service, and the ventilation buttons, which were just fine before she went in, are now not directing air to the windscreen, floor etc. Rather air is just coming out the face vents. Is this maybe a fuse issue, or has something been 'bumped' during the service? Cheers!

May 24th, 2006, 14:54	#2
morsing Premier Member Last Online: Today 12:43 Join Date: Dec 2001 Location: Aylesbury View Photos By: morsing	Buttons? Do you mean the sliders? Or the things on the vents themselves? __________________ --- '89 Volvo 240GLT B230E/AW70 '14 Volvo V70 SE D4/M66 FWD '70 Chevrolet Chevelle Malibu '95 Saab 9000 CSE 2.0 Turbo Auto

May 24th, 2006, 14:56	#3
Alec Dawe Former Support Team Last Online: Jan 26th, 2024 11:26 Join Date: Jan 2006 Location: Nr Norwich	Vent Buttons????? Oh I see you're in Australia, so I suspect that you've got a different arrangement for heating and ventilation. Hmmm, not seen any 240 with button control all rotary knobs and slides here __________________ Alec. (My other car is a WD 2-10-0)

May 24th, 2006, 15:06	#4
Alec Dawe Former Support Team Last Online: Jan 26th, 2024 11:26 Join Date: Jan 2006 Location: Nr Norwich	AH!!! Just looked in the Haynes manual, and found an American spec picture with one rotary knob, one slider, and three push buttons for air direction, so I suspect that yours is the same. Looking at the picture, it seems that the air flow is operated by the push buttons, which are powered from a vacuum tank which seems to be located behind the push button panel somewhere, (looks like 4 tennis ball sizes balls joined together in a row!), taking its supply from somewhere on the inlet manifold, (pic is not very clear). The vacuum pipes then go to vacuum operated diaphragm actuators on the air supply trunkings. I would suspect then that either a mechanic has knocked off the vacuum hose from the engine somewhere, or that one of the hoses is kinked/blocked, or holed in some way. The drawing also shown a non-return valve in the system, just behind the push button panel in the centre consol. That might have become deranged or blocked. Looking at the drawing, the push buttons are all vacuum, no electrics involved (apart from the obvious like the fan motor etc) so I doubt its a fuse if you've got air coming from some of the vents. Have a scout round for loose pipes, holes, blockages etc. __________________ Alec. (My other car is a WD 2-10-0) Last edited by Alec Dawe; May 24th, 2006 at 15:13.

May 25th, 2006, 10:09	#6
morsing Premier Member Last Online: Today 12:43 Join Date: Dec 2001 Location: Aylesbury View Photos By: morsing	It's because you have the A/C system. The vents are vacuum controlled because it has to open different ones automatically for the A/C ventilation I believe. __________________ --- '89 Volvo 240GLT B230E/AW70 '14 Volvo V70 SE D4/M66 FWD '70 Chevrolet Chevelle Malibu '95 Saab 9000 CSE 2.0 Turbo Auto

May 24th, 2006, 22:56	#5
roverlei Guest Location:	Thanks for that! I didn't know we were special down here and that everyone else was having to make do with sliders!

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