SixSeriesCSi

iTrader: (11)

My blower works, I can change between different speeds for the fan. I can not switch bewtween vent settings, all I have is defrost. If I move the lever from ac-economy-heat, it all comes out of the vents. Keep in mind that my A/C does not work. It hasn't worked since I bought the car. I noticed I have a disconnected vacum hose in the engine compartment, that appears to come from the firewall.

JamesC

iTrader: (5)

Defrost is the default setting when there's a vac leak. Check the disconnected hose.

JamesC

SixSeriesCSi

iTrader: (11)

I checked that hose and it is disconected, for sure. Question is where does it go? Any photo's?

Ward

iTrader: (1)

It should just be hooked up to manifold vacuum. I have mine connected to the fitting on the back of the plenum. There is also supposed to be a one-way valve connected in line with it. This lets the HVAC servos hold their vacuum (and hold their position) at higher RPM, when manifold vacuum is low. It's not totally critical, but without it the vents will switch to defrost at higher RPM.

Pocket

iTrader: (24)

Over near the HVAC box, there should be two hard vacuum tubes coming out. One about 10", the other nearly double that. Short one goes to manifold vacuum. Long to the heater core diverter valve

Commonly the diverter valve is removed, then the vacuum line must be plugged for HVAC controls to function

SixSeriesCSi

iTrader: (11)

Dear Mr. Pocket, can I have a photo??? Not to familiar with the HVAC Box or the Heater Core Diverter Valve. I would like to thank everyone for their support on this matter. California is starting to warm up, and this is an effort to fix my A/C. The vents are my starting point. I really appreciate your help on this matter. Thanks guys...

Pocket

iTrader: (24)

HVAC box is the big black box on the pass side of the firewall. The mini-harness comes out of the firewall behind the pass cyl head

Pics of the valve
https://www.thirdgen.org/forums/tpi/...ble-setup.html

SixSeriesCSi

iTrader: (11)

Ugh, Still confused. I don't own a digital camera. Little help?

SixSeriesCSi

iTrader: (11)

Well I figured it out but...

Still nothing. I connected the small one to the plenum, the long one to the diverter valve. Does someone have a Vacum Diagram? If there is a leak I'm going to try and find it. Can someone be so kind as to help out???

SixSeriesCSi

iTrader: (11)

I finally sorted it out. One last thing...

Sometimes it takes a minute it for change from defrost to vents? Sometimes a real long time? What could it be?

Pocket

iTrader: (24)

Vacuum leak

Do you still have the vacuum canister?

Drew

iTrader: (58)

Usually if everything is hooked up, the problem with the vacuum operated vents, is the valves in the control unit are broken. There are two of them, with plastic keepers that hold them together. They get brittle and the tabs break, and then they leak.

Also the various vacuum operated doors can get sticky. The foam rubber that was used to seal the joints usually is broken down into a sticky mess. Heater core failures can also result in rusted parts in the hvac box.

SixSeriesCSi

iTrader: (11)

Can I see a picture of the vacuum canister, please ?

Pocket

iTrader: (24)

Bottom of the drivers side battery tray. Its a big ball

SixSeriesCSi

iTrader: (11)

Oh, That thing. Let me check!