A/C & ventilation system issues

Skinny_Dave · Post by **Skinny_Dave** » Thu Nov 12, 2009 2:02 pm

I have an issue with my 92 L-Series where the air vent automatically selects the "feet" setting when the A/C is switched on. No amount of pressing all of the ventilation control buttons will change anything. When I am just using the fan without the A/C, I can select all vents normally, though I don't get much flow, even when the fan is on high.

Is it worth me taking the dash to pieces to check this? I'm wondering if it could be just a matter of replacing a rubber vacuum hose(s), or if there are electrics, or just manual linkages controlling the vent selection? I've just never seen how these things operate.

Cheers,
Dave

Gannon · Post by **Gannon** » Thu Nov 12, 2009 3:17 pm

It is possible that there is a mixup of hoses near the drivers side strut tower.

Up near the firewall, behind the strut tower is a white vacuum canister, a heap of hoses and a soleniod valve to activate the 'idle up' when the air con is on.

Im guessing that there is an air leak in one of the hoses (probably the one that goes from the air con 'idle up solenoid' to the idle up articulator) There must also be a hose mix up because there is a one way valve on the canister and it is the last thing before the vent controls
So when you turn on the air con, the vacuum that normally operates the vent controls is leaking and the vents normally default to foot when there is no vacuum.

wagonist · Post by **wagonist** » Fri Nov 13, 2009 7:41 am

The other possible cause is that one of the vacuum hoses has come off.

With the way the actuators work, when the fan is blowing, it tends to move the flap to the feet position

Start from the engine bay & work your way along the lines, though it may mean you'll need to remove the dashboard.

tony · Post by **tony** » Sun Nov 15, 2009 3:57 am

my problem is I can't get the swine to blow through the dash vents. it has been standing for a while so there may be something seized or perished.
it normally works well.

Skinny_Dave · Post by **Skinny_Dave** » Sun Nov 15, 2009 6:41 am

Spot on guys, there was a crack in one of the vacuum hoses in the engine bay. That has been replaced, and I'm now getting about a 50/50 flow through the dash and feet vents when the face option is selected. There must be another dodgy hose behind the dash that I'll look for when I do the stereo, but at least the cabin is cooling better now. Thanks heaps.

Dave