The AC/Heater unit located under the glove compartment clicks all the time. It still blows cold/hot air but clicks. It'll go away if I change the setting for a second, i.e. move to defrost from blowing on the floor, but starts back up again. This is a 1997 Tahoe. I'd like to be able to do it myself if possible. If not, any idea on a price for a fix done by a mechanic? Any idea what this might be? Your thoughts are much appreciated. Thanks.

 

I have the same problem with my 2003 Suburban. I would be interested to know the answer as well.

 

Don't know about the 97, but the 2003, its probadly the actuator thats located above the right side of the hump. http://www.rockauto.com/catalog/raframecatalog.php heater blend door actuator