'07 Tahoe HVAC issues

[garrettpsu]

I purchased this Tahoe about a year ago and on the drive home with the heater on, the vents were not working correctly. The defrost wasn't working 100% and only half the window was getting "defogged".

I assumed it was the passenger side blend door and replaced it. It seemed to fix the issue in the colder months.

This summer I started having somewhat similar issues. On hot days here in VA (90 or so), I put the AC on auto and everything would work great. But at some point when the interior cools down, something changes in the vents. AC stops blowing out the front vents and the system sounds like it's blowing air only internally and gets loud. Nothing changes on the controls, but very little cold air is coming out ANY vent and the system is loud. Once the vehicle is off for an hour and you start back up, all is well again and AC is working as it should.

Any suggestions as to what this would be? It almost sounds like a blend door issue - them closing down air getting to the cabin.

Thanks in advance. I tried searching, but it's hard to be specific as to what to search.

 

[kmickey]

I know this is an old post, but I'm having the same issue. The dealer cannot figure it out.
Was there a solution to this?

 

[Tahoe14]

He may have re-posted in the 07 section since this is the 15+ section.

 

[SSV4x4]

You have 3 control boxes that control this behind the dash. You will have to replace the one having the problem and then have the BCM updated. I had the same problem with my 07 and 08 PPV Tahoes prior to upgrading to 16 models.