Hello, I have a 2000 Malibu, the vent selector is not working, air only comes out from the dash vents, it doesn't matter what I turn the selector **** to. any ideas? thanks

 

The mode selector is a rotary vacuum switch which applies and bleeds vacuum to various vacuum actuators to open and close air doors. The source of the vacuum is a port on the intake manifold near the throttle body. There's a vacuum line between it and the vacuum reservoir tank behind the firewall. Check to make sure this line isn't unplugged or collapsed. Beyond that, I'm not sure how far you want to take it but you'll have to start taking things apart inside.

 

"The mode selector is a rotary vacuum switch which applies and bleeds vacuum to various vacuum actuators to open and close air doors. The source of the vacuum is a port on the intake manifold near the throttle body. There's a vacuum line between it and the vacuum reservoir tank behind the firewall. Check to make sure this line isn't unplugged or collapsed. Beyond that, I'm not sure how far you want to take it but you'll have to start taking things apart inside."

I checked under the hood, at the port on the intake, the line is plugged in.
I did take the selector conrol out to see if the lines are intact and they are, so I'm assuming the issue is with the lines to the resevoir tank like you suggested, but I cannot locate it, when you say behinde the firewall do you mean inside the car or in the engine bay?
I also notices the the fan setting 1 & 2 do not work only 3 and up.
Thanks

 

The vacuum reservoir tank is attached to the HVAC module assembly (the big black box behind the radio that contains the heater core and A/C evaporator). In order to get to it, you'll have to drop the HVAC module assembly (not for the faint of heart). But, first pull the vacuum supply harness (that's the one with two tubes) from the back of the HVAC control module and then check for the presence of vacuum with the engine on.

The intermediate fan setting not working is almost always the blower resistor pack, located next to the blower motor. You can't miss it, it's the one with 2x4 electrical connector.

 

Thanks for your help .. I will try checking the vacuum this Sunday, I don't think I can to tackle droping the HAVC module assembly

 

Just for thr record, I went to the junk yard and bought a climate control selector unit $30, installed it and everything works.

 

Congrats. Thanks for the update.

 

I pulled the vacuum supply harness from the back of the HVAC control module. There is an orange and brown hose. There is only vacuum at the brown hose. Should there be vacuum in both?

With the vacuum supply harness disconnected I moved the selector dial and the vacuum stops on any setting with defrost. Is this normal?

While I was doing this I heard something adjust inside the dash. When I reconnected the vacuum harness the selector switch works fine. Might this indicate the source of the problem in the climate control head/****?

 

What is the problem? The way this thing works is a vacuum source to the controller. You select what you want, it directs vacumm to the actuator doors accordingly. The default or if there is a problem with the controller it will default to defrost. You should see different colors of hose or stripes on them, that designates defrost, supply, dash vent floorboard ect.