My moms trailblazer does that. That sheot is so damn annoying just blowing when things are off. I don't notice much in the gp but I can feel some heat coming from somewhere upfront floor or dash I don't know.

Out here around White Sands/Las Cruces/Alamogordo, the winds can easily get up around 50-75 mph sustained, so having that "flow-through" venting is actually a blessing for us: I have NO worries about wind/air pressure blowing MY glass out like so many other vehicles here.

why does my fan run when i have my system is off

The fan is not running, its jsut the outside air coming in cuz there is nothing blocking off the air vents... I belive it is a BAD GM design, everyone I know with a GM vehicle does it, and everyone i know with Dodge or Ford or dare I say it (rice), have a door that cuts off the vent when it is turned off so air does not come in

problem solved guys, I will post some pics of the install for more info to anyone that needs them. Thanks again.

My Dodge doesn't cut off the air, acts just like the GP in that regard.

If you put your controls on recirculate that will close off most of the outside air.

But mine does not have an option to recirculate the air

On the digital iirc it's on the mode button. I'll have to confirm it later.

I have a manual control, I was looking into upgrading it, but saw what it took, and decided against that. Just something ill have to live with

I had the same problem, with only 5 working... occasionally. I changed the resistor and the problem is the same. Only 5 works and not all the time. Could this mean the blower motor is dead or nearly dead too?

Or is it the switch?

My local dealer will diagnose the problem but he wants $60 just to do that!

HELP!!!!

Doesn't MAX recirc?

Also, I think you can divert all the blowing to the floor at least, by setting it to that. Should close up the passage to the top vents.

I'm at a loss here. I don't have air comming in thru the vents when the air system is off. I've had this car for 4 years and havent had that happen. My climate control is digital, so does that have anything to do with it....

Didnt know that about MAX, I will try that out. Thats what I do is Divert it to the Feet, but My a/c compressor stopped working, so when its hot outside and with the temp all the way on cold, its HOT air blowing at my feet, drives me insane! But winter, dont have that much of a problem, cept in the afternoon when its up to the 70's

When I don't want air blowing on me, I switched it to defroster. I'll try max and see how that works.

BTW, I just got done installing a resistor on my GP... OMG what a pain! I just lost a lot of respect for GM engineers.