no air

[Joe Wilson]

I have an 04 Cavalier and when I turn on the heater or A/C there isn't enough air coming through the vents. I owned a 96 Cavalier before this one and it had lots of air coming through. Anybody know where to start?

[Classicrocjunkie]

Is the fan blowing at all speeds?
NO? - Blower motor resistor
Yes - Check the inlet under the wiper arm black vent cover thingy outside the car for clogging.

[Joe Wilson]

The blower works great on all speeds and a couple of hours ago I checked the vent by the windshield wiper motor and took a vacuum cleaner to it. I think now that probably it must be the vent door that's not in the right position. It does put a lot of air out by your feet, just not thru the upper air vents.

[manicmechanix]

Sounds like your mode door is not in the right position. Sometimes the vaccuum hose connection can get disconnected behind the mode selector switch. You could also check the vacuum hose under the hood for the HVAC is connected securely. Otherwise you are going to have to take the HVAC assembly out and that should be fun .

[Classicrocjunkie]

Originally Posted by manicmechanix

Sounds like your mode door is not in the right position. Sometimes the vaccuum hose connection can get disconnected behind the mode selector switch. You could also check the vacuum hose under the hood for the HVAC is connected securely. Otherwise you are going to have to take the HVAC assembly out and that should be fun .

Nice try, the 00+ are not vacuum controled like 95-99 were. They are cable operated vent selectors. There is still a foam filter inside the black Hvac unit itself which could be clogged.

[manicmechanix]

Originally Posted by Classicrocjunkie

Nice try, the 00+ are not vacuum controled like 95-99 were. They are cable operated vent selectors. There is still a foam filter inside the black Hvac unit itself which could be clogged.

Did they change to a cable operated mode selector in 2000? I didn't think about the 2000 up being changed. Well I'm not a Cavalier expert for all years, I don't own one anymore. Usually cables don't give trouble but the problem could still be in the mode selector if he has good flow out the floor vents.

[Classicrocjunkie]

Originally Posted by manicmechanix

Did they change to a cable operated mode selector in 2000? I didn't think about the 2000 up being changed. Well I'm not a Cavalier expert for all years, I don't own one anymore. Usually cables don't give trouble but the problem could still be in the mode selector if he has good flow out the floor vents.

Yep, in 2000 when GM switched to the class II they redesigned everything. Including the HVAC box.

[Joe Wilson]

I have cold and hot air coming out the vents; the problem is the hot air seems to all come out the ac vents and the cold air comes out at your feet.

[J-Ri]

The cold air is more dense, so it is sinking down while the hot air rises

Did you check those cables? Might have one off and the difference in the direction of airflow from heater core to evaporator might be pushing the mode door a bit. It's gotta be something fairly simple, the whole system is made up of a lever, a cable, and a door.

[Joe Wilson]

Can I get to this from under the dash or will I have to tear the dash apart? I'm kinda big and don't know if I can squeeze under that dash or not. I felt under there today and didn't feel any rods or levers so it must be up in there a ways or maybe someone already tried to fix it and broke it off!!

[Joe Wilson]

You were absolutely correct about the cable operated vent door. I felt under there until I found a cable with a loop on the end, disconnected from anything, and I felt a little more and found a lever with a ball on the end. I slipped the loop over the ball and now the air comes out where it's supposed to! Thanks a lot, I appreciate your help.

[Dadcanfixit]

I just finished fixing my daughters 2004 cavalier, it wouldnt blow out defrost or the dash vents. GM has a notice out on this blaming this on a cable bent or wiring harness interfering with operation. I bought the cable to replace it, but I took apart the top of dash and found that the flapper door controlling the air flow was stuck, I pushed it and the door dropped down from upper position. Now the air flow works fine. I did notice that when removing the radio, its wiring harness was jammed up behind the radio putting pressure on the AC plastic housing right where the flapper was stuck. So I assume that this was the source of the problem. I pulled the wiring harness up slightly when reinstalling the radio. There is a pin at the back of the radio that if it hits the wires will cause them to jam against the housing. AC now works fine at all positions and I did not install a new cable. Caution to pre 2002 owners check about the radio theft codes first before cutting power.